1. 

This request for a preliminary ruling was made in proceedings involving an application by a convicted person for the deduction from the total custodial sentence served in the Member State that issued a European arrest warrant (the Republic of Poland) of the period during which the Member State that executed the warrant (United Kingdom of Great Britain and Northern Ireland) imposed a curfew together with electronic monitoring and other restrictive measures.

2. 

By the question it submits for a preliminary ruling, the Sąd Rejonowy dla Łodzi-Śródmieścia w Łodzi (District Court, Łódź, Poland) essentially enquires whether measures such as those at issue in the main proceedings may be classified as ‘detention’ within the meaning of Article 26(1) of Framework Decision 2002/584/JHA, ( 2 ) giving the Court the opportunity to rule for the first time on the interpretation of that provision.

3. 

Although, at first sight, it might be concluded that the concept of ‘detention’ within the meaning of Article 26(1) of the Framework Decision covers only the deprivation of liberty stricto sensu, it is apparent from the interpretation of that provision in accordance with the fundamental rights enshrined in Article 6 TEU and reflected in the Charter of Fundamental Rights of the European Union (‘the Charter’) that the concept of detention may also encompass measures involving a restriction of liberty which, depending on its severity, may be treated in the same way as a deprivation of liberty.

4. 

It is in the light of the case-law of the European Court of Human Rights that it is necessary to assess whether, in this case, the measures imposed by the executing Member State, on account of the combination of measures, their seriousness and duration, involve a restriction of liberty comparable to imprisonment with the result that they must be deducted from the total period of detention to be served in the Member State that issued the European arrest warrant.

5.

Article 6 TEU provides:

‘1.   The Union recognises the rights, freedoms and principles set out in the Charter …, which shall have the same legal value as the Treaties.

The provisions of the Charter shall not extend in any way the competences of the Union as defined in the Treaties.

The rights, freedoms and principles in the Charter shall be interpreted in accordance with the general provisions in Title VII of the Charter governing its interpretation and application and with due regard to the explanations referred to in the Charter, that set out the sources of those provisions.

2.   The Union shall accede to the European Convention for the Protection of Human Rights and Fundamental Freedoms[, signed in Rome on 4 November 1950 (“the ECHR”)]. Such accession shall not affect the Union’s competences as defined in the Treaties.

3.   Fundamental rights, as guaranteed by the [ECHR] and as they result from the constitutional traditions common to the Member States, shall constitute general principles of the Union’s law.’

6.

Under Article 1(1) of Protocol No 30 on the application of the Charter of Fundamental Rights of the European Union to Poland and to the United Kingdom, ‘the Charter does not extend the ability of the Court of Justice of the European Union, or any court or tribunal of Poland or of the United Kingdom, to find that the laws, regulations or administrative provisions, practices or action of Poland or of the United Kingdom are inconsistent with the fundamental rights, freedoms and principles that it reaffirms’.

7.

Article 6 of the Charter guarantees that ‘everyone has the right to liberty and security of person’.

8.

Under Article 49(3) of the Charter, ‘the severity of penalties must not be disproportionate to the criminal offence’.

9.

According to Article 50 of the Charter, ‘no one shall be liable to be tried or punished again in criminal proceedings for an offence for which he or she has already been finally acquitted or convicted within the Union in accordance with the law’.

10.

Recital 12 of the Framework Decision states that that decision respects fundamental rights and observes the principles recognised by Article 6 TEU and reflected in the Charter, in particular Chapter VI thereof.

11.

Article 1(3) of the Framework Decision recalls that it ‘shall not have the effect of modifying the obligation to respect fundamental rights and fundamental legal principles as enshrined in Article 6 of the Treaty on European Union’.

12.

Article 26 of the Framework Decision, entitled ‘Deduction of the period of detention served in the executing Member State’, provides, in paragraph 1 thereof:

‘The issuing Member State shall deduct all periods of detention arising from the execution of a European arrest warrant from the total period of detention to be served in the issuing Member State as a result of a custodial sentence or detention order being passed.’

13.

Article 63(1) of the Criminal Code (kodeks karny) of 6 June 1997 ( 3 ) lays down an obligation to deduct from the total custodial sentence the period of de facto deprivation of liberty served by the convicted person during the procedure.

14.

Article 607f of the Code of Criminal Procedure (kodeks postępowania karnego) of 6 June 1997 ( 4 ) contains a provision implementing Article 26 of the Framework Decision. It is worded in terms similar to Article 63(1) of the Criminal Code. However, its scope is limited to the deprivation of liberty associated with the execution of a European arrest warrant.

15.

In 2007, a Polish court imposed a custodial sentence on Z of three years and two months. Since Z had left Poland, the competent court issued a European arrest warrant. On 18 June 2014, Z was arrested by the United Kingdom authorities in execution of the European arrest warrant.

16.

Between 19 June 2014 and 14 May 2015, Z was subject to a curfew condition alongside an electronic monitoring condition.

17.

On 14 May 2015, Z was surrendered to the Polish authorities. He subsequently applied to the referring court to have the period during which he was subject to the curfew and electronic monitoring in the United Kingdom deducted from the total period of detention to be served in Poland.

18.

In those circumstances, the Sąd Rejonowy dla Łodzi-Śródmieścia w Łodzi (District Court, Łódź) decided to stay the proceedings and to refer the following question to the Court of Justice for a preliminary ruling:

‘Must Article 26(1) of [the Framework Decision], in conjunction with Article 6(1) and (3) [TEU] and Article 49(3) of the [Charter], be interpreted as meaning that the term “detention” also covers measures applied by the executing Member State consisting in the electronic monitoring of the place of residence of the person to whom the arrest warrant applies, in conjunction with a curfew?’

19.

The referring court points out that, although the execution of some custodial sentences in the form of a curfew with electronic monitoring is not unknown in the Polish legal system, it is not an option for all sentences. Furthermore, Polish law makes no provision for curfews with electronic monitoring as a detention order. Thus, there is some uncertainty as to whether it is possible to deduct periods during which such a measure was applied from the total period of detention.

20.

The national courts seem to interpret the concept of ‘detention’ within the meaning of Article 26(1) of the Framework Decision in the light of the corresponding provisions of domestic law, namely Article 63(1) of the Criminal Code. Accordingly, as the term used in that provision — ‘de facto deprivation of liberty’ — is quite narrow in scope, there is a perception that the national courts are somewhat reluctant to allow a period of curfew with electronic monitoring to be deducted from a custodial sentence. However, the Trybunał Konstytucyjny (Polish Constitutional Court) has, on several occasions, declined to rule out that possibility. It has nevertheless made clear that the reply in the present case depends on whether the conditions for the execution of such a measure are such that that measure may be treated in the same way as a de facto deprivation of liberty.

21.

The referring court also relies on the case-law of the European Court of Human Rights on the interpretation of the concept of ‘deprivation of liberty’ for the purposes of Article 5 of the ECHR as a means of flagging up the different approaches to that concept as interpreted by the international courts. In addition, it relies on the provisions of the Charter, particularly Article 49(3) thereof, and wonders whether the possible refusal of the application in the main proceedings would infringe the principle of proportionality as referred to in that article.

22.

This request for a preliminary ruling was lodged at the Court on 25 May 2016. The Polish Government and the European Commission submitted written observations.

23.

At the hearing held on 4 July 2016, the interested persons referred to in Article 23 of the Statute of the Court of Justice of the European Union, and in particular the Polish and United Kingdom Governments, were asked to answer the following questions:

24.

The United Kingdom Government was also asked to provide the Court with details of the provisions of national law which were applied in the present case and of the precise measures imposed on Z.

25.

The Polish, German and United Kingdom Governments as well as the Commission submitted oral observations at the hearing.

26.

The Polish Government submits that a literal interpretation of Article 26(1) of the Framework Decision does not prevent the concept of detention being considered, under certain circumstances, to encompass measures other than conventional forms of deprivation of liberty, such as measures whereby the residence of the person sought is placed under electronic monitoring and a curfew imposed.

27.

The Polish Government contends that the interpretation of the Framework Decision must take account of the rights and principles to which the Framework Decision itself refers, particularly those laid down in Article 6 TEU and reflected in the Charter. In that context, it refers to the case-law of the European Court of Human Rights concerning the interpretation of the concept of ‘deprivation of liberty’ for the purposes of Article 5 of the ECHR. In the light of that case-law, the Polish Government argues that Article 26(1) of the Framework Decision does not refer exclusively to police custody, pre-trial detention or other conventional forms of deprivation of liberty. The concept of detention covered by that provision must be given a broader interpretation, that is, as encompassing all measures which entail, in essence, a de facto deprivation of liberty.

28.

If the opposite view were taken, some periods of de facto deprivation of liberty might not be credited, which would infringe the principle of proportionality laid down in Article 49(3) of the Charter. In that respect, the Republic of Poland also submits that Article 26(1) of the Framework Decision gives concrete expression to the principle of proportionality. Under that provision, periods of detention arising from the execution of a European arrest warrant are to be deducted from the total period of detention to be served in the issuing Member State, so that the person prosecuted is not obliged to serve a double sentence, having the same effect, for a single offence.

29.

It is therefore for the court before which the case has been brought in the Member State that issued the European arrest warrant to assess whether there has been a de facto deprivation of liberty due to the application of measures other than conventional forms of deprivation of liberty. That court will have to determine whether the measure applied in the executing Member State reaches a sufficient level of intensity and hardship enabling it to be treated in the same way as a deprivation of liberty for the purposes of Article 26(1) of the Framework Decision and, therefore, to be credited towards the length of the sentence passed.

30.

In the light of the considerations set out above, the Republic of Poland submits that the concept of detention also covers measures applied by the executing Member State consisting in the electronic monitoring of the place of residence of the person to whom the arrest warrant applies, combined with a curfew, provided that those measures are of such a level of intensity and hardship that they can be regarded as analogous to a deprivation of liberty.

31.

The German Government argues that electronic monitoring measures are not, in themselves, measures involving deprivation of liberty, but rather a means of checking that such deprivation is implemented.

32.

As regards the question put by the referring court, the German Government endorses the argument advanced by the Commission in its written observations, which is summarised in point 42 of this Opinion.

33.

As to the questions put by the Court, the German Government, first, expresses doubts about the effect of Article 49(3) of the Charter on the interpretation of Article 26(1) of the Framework Decision and, secondly, contends that Article 26(1) of the Framework Decision does not confer any discretion as to the crediting in the issuing Member State of periods during which measures such as those at issue in the main proceedings were applied in the executing Member State.

34.

The United Kingdom Government argues that the concept of ‘detention’ within the meaning of Article 26(1) of the Framework Decision covers, in principle, only measures involving deprivation of liberty stricto sensu. That is the only valid conclusion to be drawn from the wording of that article, the legislative context of the Framework Decision (in which reference must be made to Article 12) and EU law (particularly Framework Decision 2009/829/JHA ( 5 )), as well as Article 6 of the Charter.

35.

As far as the United Kingdom Government is concerned, Article 49(3) of the Charter is irrelevant to the interpretation of Article 26(1) of the Framework Decision and there is no discretion as to the crediting of periods during which measures such as those at issue in the main proceedings were applied in the executing Member State if it is found that those measures involve ‘detention’ within the meaning of Article 26(1) of the Framework Decision.

36.

For its part, the Commission observes that Article 26(1) of the Framework Decision must be read and interpreted in the context of the scheme of the surrender procedures established by that instrument. In its opinion, it is apparent from that scheme that the surrender procedures and the effects of the European arrest warrant are based on cooperation between the judicial authorities of the Member States. This requires a common understanding of key concepts such as ‘detention’, which is decisive for the resolution of the present case.

37.

Since the concept of detention is not expressly defined either in the Framework Decision or in any other relevant rule of EU law, it should be interpreted having regard to the letter as well as the broad logic and purpose of the relevant provision in the scheme of the Framework Decision.

38.

The Commission argues that if, in accordance with a literal interpretation, ‘detention’ is limited to the deprivation of a person’s liberty to come and go following his arrest and imprisonment, then, from the standpoint of a systematic interpretation, it is apparent from Article 12 of the Framework Decision that a distinction should be drawn between, on the one hand, ‘detention’ and, on the other, ‘[provisional] release’ coupled with measures necessary ‘to prevent the person absconding’. In essence, this provision thus distinguishes between measures involving deprivation of liberty of movement (detention) and measures not involving deprivation of liberty which nevertheless limit that liberty, where appropriate, in order to prevent a person absconding.

39.

The Commission observes that the same logic can be found in Framework Decision 2008/947/JHA ( 6 ) and Framework Decision 2008/909/JHA, ( 7 ) concerning sentenced persons, as well as in Framework Decision 2009/829, concerning persons subject to ongoing criminal proceedings. It can be seen from those decisions that supervision or monitoring measures, such as electronic monitoring, fall within the scope of measures not involving deprivation of liberty.

40.

The Commission moreover notes that it is the combination, seriousness and duration of the supervision or monitoring measures which may have the effect of ‘turning quantity into quality’, so that the restrictions on freedom of movement resulting from the measures as a whole must be treated, on account of their intensity, in the same way as a measure involving deprivation of liberty.

41.

So far as concerns a teleological approach, the Commission maintains that Article 26 of the Framework Decision seeks to remedy a shortcoming in the previous multilateral system of extradition where, as stated in the Proposal for a Framework Decision COM(2001) 522 final, ( 8 )‘the possibility of deducting the period served in prison in the extradition process from the total sentence to be served was not always available’. Thus, Article 26 requires the judicial authority of the issuing Member State to deduct from the sentence the total period of detention served in the executing Member State. In that context and taking account of the principle of mutual recognition, Article 26 of the Framework Decision should be interpreted by reference to the development of alternative measures to detention in the conventional sense of that term.

42.

The Commission concludes that the concept of ‘detention’ within the meaning of Article 26 of the Framework Decision includes measures involving deprivation of liberty ordered by the judicial authority of the executing Member State with a view to executing a European arrest warrant. In addition to imprisonment, measures to supervise and monitor the residence of the person to whom the European arrest warrant applies must be treated in the same way as measures involving deprivation of liberty where the former, on account of the combination of measures, their seriousness and duration, deprive the person in question of his physical freedom in a manner comparable to imprisonment. It is for the judicial authority of the issuing Member State to determine whether that is the case by taking account of all the circumstances of the case on the basis of the information supplied by the executing judicial authority.

43.

According to the referring court, Z was arrested in the United Kingdom on 18 June 2014 and remained in detention there until 19 June 2014. On that date, he was released on bail of GBP 2000 on condition that he stayed at the address he had given between 22.00 and 7.00, a condition that was coupled with electronic monitoring. In addition, Z was: (i) required to report to a police station, initially seven times a week and, after three months, three times a week, between 10.00 and 12.00; (ii) prohibited from applying for foreign travel documents; and (iii) required to keep his mobile telephone switched on and charged at all times. Those measures were applied until 14 May 2015, whereupon he was surrendered to the Polish authorities.

44.

It is against that background that, through the reference for a preliminary ruling from the Sąd Rejonowy dla Łodzi-Śródmieścia w Łodzi (District Court, Łódź), the question arises whether the conditions imposed on Z between 19 June 2014 and 14 May 2015 amount to ‘detention’ within the meaning of Article 26(1) of the Framework Decision.

45.

As is usual in EU law, the use of categories intended to apply in all national legal systems is feasible only in so far as those categories are reduced to a unitary and uniform concept for all the Member States.

46.

As the referring court pointed out, the Court has consistently held that ‘the need for the uniform application of EU law and the principle of equality require that the terms of a provision of EU law which makes no express reference to the law of the Member States for the purpose of determining its meaning and scope must normally be given an autonomous and uniform interpretation throughout the European Union, which must take into account the context of that provision and the purpose of the legislation in question’. ( 9 )

47.

The notion of ‘detention’ in the Framework Decision must itself be based on respect for fundamental rights and observance of the principles recognised by Article 6 TEU and reflected in the Charter, bearing in mind that fundamental rights, as guaranteed by the ECHR and as they result from the constitutional traditions common to the Member States, form part of EU law as general principles, under Article 6(3) TEU. ( 10 )

48.

This position of principle is the linchpin of the Framework Decision, Article 1(3) of which recalls that that decision, which aims to establish a simplified and effective system for the surrender of persons sentenced for, or suspected of having committed, a criminal offence, ‘shall not have the effect of modifying the obligation to respect fundamental rights’.

49.

A fortiori, the same is true of Article 26(1) of the Framework Decision, since the objective of that provision is to protect the right to liberty of the person requested under the European arrest warrant by including an obligation to deduct from the total period of detention to be served in the issuing Member State periods of detention already served in the executing Member State for the purpose of executing the warrant.

50.

As is apparent from the heading under which it appears, the purpose of Article 26 of the Framework Decision is quite clear: it is concerned with the ‘deduction of the period of detention served in the executing Member State’, particularly ‘all periods of detention arising from the execution of a European arrest warrant’ (Article 26(1)). The ‘detention arising from the execution of a European arrest warrant’ is none other than that specified in Article 11 of the Framework Decision, concerning the rights of the requested person and, in that connection, ‘arrested for the purpose of the execution of a European arrest warrant’ (Article 11(2)).

51.

In view of the connection in meaning underpinning the relationship between, on the one hand, Article 26(1) and, on the other, Articles 11 and 12 of the Framework Decision, the differences between the language versions of the first of those provisions are not, in my opinion, an obstacle to that provision being properly understood. ( 11 )

52.

For the drafter of the Framework Decision, the concept of arrest ‘for the purpose of the execution of a European arrest warrant’ is the same as the concept of ‘detention’. Indeed, Article 12 of the Framework Decision provides that ‘when a person is arrested on the basis of a European arrest warrant, the executing judicial authority shall take a decision on whether the requested person should remain in detention, in accordance with the law of the executing Member State’, ( 12 ) the alternative to such ‘detention’ being that the person may be ‘released provisionally’, ( 13 ) which is possible ‘at any time’ under that article.

53.

The ‘detention’ is therefore nothing more than the extension of the ‘detention’ entailed by the arrest. In addition, it is the detention arising from the execution of a European arrest warrant which Article 26(1) of the Framework Decision seeks to deduct from the detention to be served in the issuing Member State as a result of a custodial sentence or detention order being passed.

54.

That being the case, I take the view that ‘detention’ within the meaning of Article 26(1) of the Framework Decision covers only situations entailing deprivation of liberty, thereby excluding, in principle, situations involving only a restriction of such liberty.

55.

That interpretation is confirmed by other provisions of EU law, such as Framework Decision 2009/829, which ‘has as its objective the promotion … of the use of non-custodial measures as an alternative to provisional detention’, ( 14 ) and Article 8 of that decision, which lists the following as measures of that kind (‘supervision measures’): ‘(a) an obligation for the person to inform the competent authority … of any change of residence …; (b) an obligation not to enter certain localities, places or defined areas …; (c) an obligation to remain at a specified place, where applicable during specified times; (d) an obligation containing limitations on leaving the territory of the executing State; (e) an obligation to report at specified times to a specific authority; (f) an obligation to avoid contact with specific persons…’. ( 15 )

56.

Since ‘arrest’ and ‘detention’ are equivalent, as pointed out above, it can be readily concluded that, in principle, the deprivation of liberty alluded to in Article 26(1) of the Framework Decision is one where the arrested person is permanently and for an extended period of time handed over to the judicial and/or administrative authorities, that is, where he is held in a public facility in conditions under which his personal autonomy is significantly curtailed.

57.

Admittedly, the difference between the concept of deprivation of liberty and that of the restriction of a person’s liberty is one of degree rather than nature or substance. It is also a question, in any case, of limitations on a person’s autonomy which are not as significant as those imposed on persons held in detention facilities or in prison.

58.

The national court refers to the case-law of the European Court of Human Rights, noting that useful interpretative guidance for our purposes can be gleaned from its rulings on Article 5 of the ECHR.

59.

In fact, rather than useful guidance, it is possible to extract real criteria for the interpretation of Article 5 of the ECHR and, in consequence, Article 6 of the Charter, in the light of which Article 26(1) of the Framework Decision should be interpreted.

60.

Through Article 26, the EU legislature sought to discharge its general obligation to comply with fundamental rights in the ambit of the Framework Decision, particularly the fundamental right to liberty guaranteed by Article 6 of the Charter, non-compliance with which may trigger, to a certain extent, on-compliance with the principle that penalties must be proportionate (Article 49(3) of the Charter) ( 16 ) and even the right not to be punished twice for the same offence (Article 50 of the Charter). ( 17 )

61.

That being the case, the concept of ‘detention’ within the meaning of Article 26(1) of the Framework Decision must be interpreted in accordance with the content of Article 6 of the Charter, since the rights recognised therein, according to the explanations relating to the Charter — which, as a way of providing guidance in the interpretation of the Charter, must be given due regard by the courts of the European Union and of the Member States (Article 52(7) thereof) — ‘are the rights guaranteed by Article 5 of the ECHR, and in accordance with Article 52(3) of the Charter, they have the same meaning and scope’.

62.

To that effect, reference must be made to the judgment of the European Court of Human Rights of 6 November 1980 in Guzzardi v. Italy, ( 18 ) in which the court stated that since the difference between a ‘deprivation of’ and a ‘restriction upon liberty’ was one of intensity and not one of nature, ‘the process of classification into one or other of these categories sometimes proves to be no easy task in that some borderline cases are a matter of pure opinion’. ( 19 ) In that case, the European Court of Human Rights stated that, in order to determine whether someone has been deprived of his liberty, ‘the starting point must be his concrete situation and account must be taken of a whole range of criteria such as the type, duration, effects and manner of implementation of the measure in question’. ( 20 ) Thus, the European Court of Human Rights found that, although it was not possible to speak of deprivation of liberty on the strength of any one of those factors taken individually, taken together they certainly raised the question of the possible application of Article 5 of the ECHR. By comparing the applicant’s stay on the island of Asinara to detention in an ‘open prison’ or in a disciplinary unit, the Strasbourg court held that the applicant’s treatment amounted to a deprivation of liberty. ( 21 )

63.

In its judgment of 2 November 2006 in Dacosta Silva v. Spain, ( 22 ) the European Court of Human Rights also held that six days’ house arrest ordered against an officer of the Guardia Civil by his superior following a disciplinary offence constituted a deprivation of liberty, as the measure required the applicant to remain at his place of residence, with permission to leave to purchase medicinal products and other necessities and to attend religious services.

64.

The concept of ‘detention’ within the meaning of Article 26(1) of the Framework Decision must be interpreted in a manner consistent with these decisions of the European Court of Human Rights, with the result that it is necessary to take the concrete situation of the person concerned as the starting point and to take account of all the circumstances in which the measures involving a restriction of liberty were implemented in the executing Member State for the purpose of executing the European arrest warrant.

65.

In principle, it is for the referring court to examine whether the measures imposed on the applicant in the main proceedings in the executing Member State amount to de facto measures involving deprivation of liberty and, if they do, to deduct them from the total period of detention to be served in the issuing Member State.

66.

To that effect, Article 26(2) of the Framework Decision provides for the transmission of ‘all information concerning the duration of the detention of the requested person on the basis of the European arrest warrant … by the executing judicial authority’, which allows the issuing Member State also to examine the actual nature of the circumstances surrounding the concrete situation of the requested person during the period of ‘detention’ by the authorities of the executing Member State.

67.

In the light of that information, the national court must determine whether there is equivalence between measures involving deprivation of liberty stricto sensu and the measures applied to the applicant in the main proceedings, in order to ascertain whether the latter measures produced a situation substantively comparable to the situation entailed by the former measures.

68.

However, in order to give the national court (and, indirectly, the other courts of the Member States) an answer which is useful in reaching a decision in the main proceedings, I am of the opinion that the Court should rule on the classification, from the standpoint of Article 26 of the Framework Decision, of the measures taken against Z after his release in the United Kingdom. My suggested answer is that, on the basis of the information provided by the Sąd Rejonowy dla Łodzi-Śródmieścia w Łodzi (District Court, Łódź) and the United Kingdom Government at the hearing, those measures cannot be classified as measures involving deprivation of liberty.

69.

The most restrictive of the measures was the obligation to remain at the stipulated address between 22.00 and 7.00 under electronic monitoring. Other, less severe measures ( 23 ) were: (i) the obligation to report to a police station, initially seven times a week and, after three months, three times a week, between 10.00 and 12.00; and (ii) the prohibition on applying for foreign travel documents. Those measures were applied between 19 June 2014 and 14 May 2015, whereupon Z was surrendered to the Polish authorities.

70.

These are therefore measures whose content and scope matches those set out in Framework Decision 2009/829, to which I referred in point 55 of this Opinion, which were conceived by the EU legislature as measures not involving deprivation of liberty. Even with reference to the case-law of the European Court of Human Rights, I do not think that the situation to which the applicant in the main proceedings was subjected can be classified as being tantamount to a deprivation of liberty.

71.

In contrast to the cases on which the European Court of Human Rights has ruled, the conditions borne by the applicant in the main proceedings involved only constraints, classifiable as restrictions on his liberty, since he was able to stay at the address he had given and was not deprived of his freedom to travel within the United Kingdom. Admittedly, he had to remain at home between 22.00 and 7.00, report to a police station, initially every day and, for most of the period concerned, three times a week, and always have his mobile telephone to hand. To my mind, these are ‘constraints’ which, even taken together, cannot be compared with those imposed on the applicants in the abovementioned cases before the European Court of Human Rights. In any event, I do not think that they entailed a limitation on the personal autonomy of Z which was so significant as to substantially diminish his personal capacity to decide on his own actions.

72.

However, it should also be noted that this conclusion relates only to the obligation to apply the deduction laid down in Article 26(1) of the Framework Decision in the main proceedings. There is nothing to prevent the referring court from deciding, on the basis of domestic law alone, to credit the periods imposed in the executing Member State towards the deprivation of liberty currently being enforced, periods which nevertheless amount to restrictions, rather than deprivations, of liberty.

73.

In more straightforward terms, EU law imposes only one obligation in this field, which could be described as a minimum obligation: to deduct periods of ‘detention’ within the meaning of Article 26(1) of the Framework Decision, it being for the national court to determine whether the measures applied to the applicant in the executing Member State amount to genuine measures involving deprivation of liberty. If the court enforcing penalties classifies those measures as measures involving deprivation of liberty (in accordance with the criteria identified in the case-law of the European Court of Human Rights), it must take them into account so that they can be deducted from the period of detention to be served in the issuing Member State, in accordance with Article 26(1) of the Framework Decision.

74.

By contrast, measures other than those involving deprivation of liberty for the purposes of Article 26(1) of the Framework Decision may also be taken into account by the national court with a view to reducing or easing the conditions of enforcement of the detention to be served in the issuing Member State, if domestic law makes provision to that effect.

75.

In the light of the foregoing considerations, I propose that the Court answer the questions referred for a preliminary ruling by the national court as follows: