29Second, as regards the criterion relating to urgency, it is necessary, in accordance with the settled case-law of the Court, to take into account the fact that the person concerned is currently deprived of his liberty and that the question as to whether he may continue to be held in custody depends on the outcome of the dispute in the main proceedings. In addition, the situation of the person concerned must be assessed as it stands at the time when consideration is given to the request that the reference be dealt with under the urgent procedure (judgment of 10 August 2017, Zdziaszek, C‑271/17 PPU , EU:C:2017:629 , paragraph 72 and the case-law cited).

30In the present instance, it is not in dispute that, at that time, the person concerned was in custody. Also, his continued detention depends on the outcome of the main proceedings, the detention measure against him having been ordered, according to the explanations provided by the referring court, in the context of the execution of the EAWs.

31In those circumstances, on 12 April 2018 the First Chamber of the Court, acting on a proposal from the Judge-Rapporteur and after hearing the Advocate General, decided to grant the referring court’s request that the present reference be dealt with under the urgent preliminary ruling procedure.

32It was also decided to remit the present case to the Court for it to be assigned to the Grand Chamber.

33First of all, it is apparent from the grounds of the order for reference and from the express mention of the judgment of 5 April 2016, Aranyosi and Căldăraru ( C‑404/15 and C‑659/15 PPU , EU:C:2016:198 ), in the first question, that the questions asked by the referring court relate to the circumstances in which the executing judicial authority may, on the basis of Article 1(3) of Framework Decision 2002/584, refrain from giving effect to a European arrest warrant on account of the risk of breach, if the requested person is surrendered to the issuing judicial authority, of the fundamental right to a fair trial before an independent tribunal, as enshrined in Article 6(1) of the ECHR, a provision which, as is clear from paragraph 5 of the present judgment, corresponds to the second paragraph of Article 47 of the Charter.

35In order to answer the questions referred, it should be recalled that EU law is based on the fundamental premiss that each Member State shares with all the other Member States, and recognises that they share with it, a set of common values on which the European Union is founded, as stated in Article 2 TEU. That premiss implies and justifies the existence of mutual trust between the Member States that those values will be recognised, and therefore that the EU law that implements them will be respected (judgment of 6 March 2018, Achmea, C‑284/16 , EU:C:2018:158 , paragraph 34 and the case-law cited).

36Both the principle of mutual trust between the Member States and the principle of mutual recognition, which is itself based on the mutual trust between the latter (see, to that effect, judgment of 10 August 2017, Tupikas, C‑270/17 PPU , EU:C:2017:628 , paragraph 49 and the case-law cited), are, in EU law, of fundamental importance given that they allow an area without internal borders to be created and maintained. More specifically, the principle of mutual trust requires, particularly as regards the area of freedom, security and justice, each of those States, save in exceptional circumstances, to consider all the other Member States to be complying with EU law and particularly with the fundamental rights recognised by EU law (judgment of 10 November 2016, Poltorak, C‑452/16 PPU , EU:C:2016:858 , paragraph 26 and the case-law cited).

37Thus, when implementing EU law, the Member States may, under EU law, be required to presume that fundamental rights have been observed by the other Member States, so that not only may they not demand a higher level of national protection of fundamental rights from another Member State than that provided by EU law, but also, save in exceptional cases, they may not check whether that other Member State has actually, in a specific case, observed the fundamental rights guaranteed by the European Union (Opinion 2/13 ( Accession of the European Union to the ECHR ) of 18 December 2014, EU:C:2014:2454 , paragraph 192 ).

38It is apparent from recital 6 of Framework Decision 2002/584 that the European arrest warrant provided for in that framework decision is the first concrete measure in the field of criminal law implementing the principle of mutual recognition.

39The purpose of Framework Decision 2002/584, as is apparent in particular from Article 1(1) and (2) and recitals 5 and 7 thereof, is to replace the multilateral system of extradition based on the European Convention on Extradition of 13 December 1957 with a system of surrender between judicial authorities of convicted or suspected persons for the purpose of enforcing judgments or of conducting prosecutions, the system of surrender being based on the principle of mutual recognition (judgment of 10 November 2016, Kovalkovas, C‑477/16 PPU , EU:C:2016:861 , paragraph 25 and the case-law cited).

40Framework Decision 2002/584 thus seeks, by the establishment of a new simplified and more effective system for the surrender of persons convicted or suspected of having infringed criminal law, to facilitate and accelerate judicial cooperation with a view to contributing to the attainment of the objective set for the European Union of becoming an area of freedom, security and justice, and has as its basis the high level of trust which must exist between the Member States (judgment of 10 November 2016, Poltorak, C‑452/16 PPU , EU:C:2016:858 , paragraph 25 and the case-law cited).

41In the field governed by Framework Decision 2002/584, the principle of mutual recognition, which, as is apparent in particular from recital 6 of that framework decision, constitutes the ‘cornerstone’ of judicial cooperation in criminal matters, is applied in Article 1(2) thereof which lays down the rule that Member States are required to execute any European arrest warrant on the basis of the principle of mutual recognition and in accordance with the provisions of the framework decision. Executing judicial authorities may therefore, in principle, refuse to execute such a warrant only on the grounds for non-execution exhaustively listed by the framework decision and execution of the warrant may be made subject only to one of the conditions exhaustively laid down in Article 5. Accordingly, while execution of the European arrest warrant constitutes the rule, refusal to execute is intended to be an exception which must be interpreted strictly (see, to that effect, judgment of 10 August 2017, Tupikas, C‑270/17 PPU , EU:C:2017:628 , paragraphs 49 and 50 and the case-law cited).

42Thus, Framework Decision 2002/584 explicitly states the grounds for mandatory non-execution (Article 3) and optional non-execution (Articles 4 and 4a) of a European arrest warrant, as well as the guarantees to be given by the issuing Member State in particular cases (Article 5) (see judgment of 10 August 2017, Tupikas, C‑270/17 PPU , EU:C:2017:628 , paragraph 51 ).

43Nonetheless, the Court has recognised that limitations may be placed on the principles of mutual recognition and mutual trust between Member States ‘in exceptional circumstances’ (see, to that effect, judgment of 5 April 2016, Aranyosi and Căldăraru, C‑404/15 and C‑659/15 PPU , EU:C:2016:198 , paragraph 82 and the case-law cited).

44In that context, the Court has acknowledged that, subject to certain conditions, the executing judicial authority has the power to bring the surrender procedure established by Framework Decision 2002/584 to an end where surrender may result in the requested person being subject to inhuman or degrading treatment within the meaning of Article 4 of the Charter (see, to that effect, judgment of 5 April 2016, Aranyosi and Căldăraru, C‑404/15 and C‑659/15 PPU , EU:C:2016:198 , paragraph 104 ).

45For that purpose, the Court has relied, first, on Article 1(3) of Framework Decision 2002/584, which provides that the framework decision is not to have the effect of modifying the obligation to respect fundamental rights and fundamental legal principles as enshrined in Articles 2 and 6 TEU and, second, on the absolute nature of the fundamental right guaranteed by Article 4 of the Charter (see, to that effect, judgment of 5 April 2016, Aranyosi and Căldăraru, C‑404/15 and C‑659/15 PPU , EU:C:2016:198 , paragraphs 83 and 85 ).

47It should thus, first of all, be determined whether, like a real risk of breach of Article 4 of the Charter, a real risk of breach of the fundamental right of the individual concerned to an independent tribunal and, therefore, of his fundamental right to a fair trial as laid down in the second paragraph of Article 47 of the Charter is capable of permitting the executing judicial authority to refrain, by way of exception, from giving effect to a European arrest warrant, on the basis of Article 1(3) of Framework Decision 2002/584.

48In that regard, it must be pointed out that the requirement of judicial independence forms part of the essence of the fundamental right to a fair trial, a right which is of cardinal importance as a guarantee that all the rights which individuals derive from EU law will be protected and that the values common to the Member States set out in Article 2 TEU, in particular the value of the rule of law, will be safeguarded.

49Indeed, the European Union is a union based on the rule of law in which individuals have the right to challenge before the courts the legality of any decision or other national measure relating to the application to them of an EU act (judgment of 27 February 2018, Associação Sindical dos Juízes Portugueses, C‑64/16 , EU:C:2018:117 , paragraph 31 and the case-law cited).

50In accordance with Article 19 TEU, which gives concrete expression to the value of the rule of law affirmed in Article 2 TEU, it is for the national courts and tribunals and the Court of Justice to ensure the full application of EU law in all Member States and judicial protection of the rights of individuals under that law (see, to that effect, judgments of 27 February 2018, Associação Sindical dos Juízes Portugueses, C‑64/16 , EU:C:2018:117 , paragraph 32 and the case-law cited, and of 6 March 2018, Achmea, C‑284/16 , EU:C:2018:158 , paragraph 36 and the case-law cited).

51The very existence of effective judicial review designed to ensure compliance with EU law is of the essence of the rule of law (judgment of 27 February 2018, Associação Sindical dos Juízes Portugueses, C‑64/16 , EU:C:2018:117 , paragraph 36 and the case-law cited).

52It follows that every Member State must ensure that the bodies which, as ‘courts or tribunals’ within the meaning of EU law, come within its judicial system in the fields covered by EU law meet the requirements of effective judicial protection (judgment of 27 February 2018, Associação Sindical dos Juízes Portugueses, C‑64/16 , EU:C:2018:117 , paragraph 37 ).

53In order for that protection to be ensured, maintaining the independence of those bodies is essential, as confirmed by the second paragraph of Article 47 of the Charter, which refers to access to an ‘independent’ tribunal as one of the requirements linked to the fundamental right to an effective remedy (judgment of 27 February 2018, Associação Sindical dos Juízes Portugueses, C‑64/16 , EU:C:2018:117 , paragraph 41 ).

54The independence of national courts and tribunals is, in particular, essential to the proper working of the judicial cooperation system embodied by the preliminary ruling mechanism under Article 267 TFEU, in that, in accordance with the Court’s settled case-law, that mechanism may be activated only by a body responsible for applying EU law which satisfies, inter alia, that criterion of independence (judgment of 27 February 2018, Associação Sindical dos Juízes Portugueses, C‑64/16 , EU:C:2018:117 , paragraph 43 ).

55Since, as stated in paragraph 40 of the present judgment, Framework Decision 2002/584 is intended to establish a simplified system of direct surrender between ‘judicial authorities’ for the purpose of ensuring in the area of freedom, security and justice the free movement of judicial decisions in criminal matters, maintaining the independence of such authorities is also essential in the context of the European arrest warrant mechanism.

56Framework Decision 2002/584 is founded on the principle that decisions relating to European arrest warrants are attended by all the guarantees appropriate for judicial decisions, inter alia those resulting from the fundamental rights and fundamental legal principles referred to in Article 1(3) of the framework decision. This means that not only the decision on executing a European arrest warrant, but also the decision on issuing such a warrant, must be taken by a judicial authority that meets the requirements inherent in effective judicial protection — including the guarantee of independence — so that the entire surrender procedure between Member States provided for by the framework decision is carried out under judicial supervision (see, to that effect, judgment of 10 November 2016, Kovalkovas, C‑477/16 PPU , EU:C:2016:861 , paragraph 37 and the case-law cited).

57Furthermore, in criminal procedures for the purpose of prosecution, or of enforcement of a custodial sentence or detention order, or indeed in substantive criminal proceedings, which lie outside the scope of Framework Decision 2002/584 and of EU law, the Member States are still obliged to observe fundamental rights enshrined in the ECHR or laid down by their national law, including the right to a fair trial and the guarantees deriving from it (see, to that effect, judgment of 30 May 2013, F, C‑168/13 PPU , EU:C:2013:358 , paragraph 48 ).

58The high level of trust between Member States on which the European arrest warrant mechanism is based is thus founded on the premiss that the criminal courts of the other Member States — which, following execution of a European arrest warrant, will have to conduct the criminal procedure for the purpose of prosecution, or of enforcement of a custodial sentence or detention order, and the substantive criminal proceedings — meet the requirements of effective judicial protection, which include, in particular, the independence and impartiality of those courts.

59It must, accordingly, be held that the existence of a real risk that the person in respect of whom a European arrest warrant has been issued will, if surrendered to the issuing judicial authority, suffer a breach of his fundamental right to an independent tribunal and, therefore, of the essence of his fundamental right to a fair trial, a right guaranteed by the second paragraph of Article 47 of the Charter, is capable of permitting the executing judicial authority to refrain, by way of exception, from giving effect to that European arrest warrant, on the basis of Article 1(3) of Framework Decision 2002/584.

60Thus, where, as in the main proceedings, the person in respect of whom a European arrest warrant has been issued, pleads, in order to oppose his surrender to the issuing judicial authority, that there are systemic deficiencies, or, at all events, generalised deficiencies, which, according to him, are liable to affect the independence of the judiciary in the issuing Member State and thus to compromise the essence of his fundamental right to a fair trial, the executing judicial authority is required to assess whether there is a real risk that the individual concerned will suffer a breach of that fundamental right, when it is called upon to decide on his surrender to the authorities of the issuing Member State (see, by analogy, judgment of 5 April 2016, Aranyosi and Căldăraru, C‑404/15 and C‑659/15 PPU , EU:C:2016:198 , paragraph 88 ).

61To that end, the executing judicial authority must, as a first step, assess, on the basis of material that is objective, reliable, specific and properly updated concerning the operation of the system of justice in the issuing Member State (see, to that effect, judgment of 5 April 2016, Aranyosi and Căldăraru, C‑404/15 and C‑659/15 PPU , EU:C:2016:198 , paragraph 89 ), whether there is a real risk, connected with a lack of independence of the courts of that Member State on account of systemic or generalised deficiencies there, of the fundamental right to a fair trial being breached. Information in a reasoned proposal recently addressed by the Commission to the Council on the basis of Article 7(1) TEU is particularly relevant for the purposes of that assessment.

62Such an assessment must be carried out having regard to the standard of protection of the fundamental right that is guaranteed by the second paragraph of Article 47 of the Charter (see, by analogy, judgment of 5 April 2016, Aranyosi and Căldăraru, C‑404/15 and C‑659/15 PPU , EU:C:2016:198 , paragraph 88 and the case-law cited).

63As regards the requirement that courts be independent which forms part of the essence of that right, it should be pointed out that that requirement is inherent in the task of adjudication and has two aspects. The first aspect, which is external in nature, presupposes that the court concerned exercises its functions wholly autonomously, without being subject to any hierarchical constraint or subordinated to any other body and without taking orders or instructions from any source whatsoever, thus being protected against external interventions or pressure liable to impair the independent judgment of its members and to influence their decisions (see, to that effect, judgment of 27 February 2018, Associação Sindical dos Juízes Portugueses, C‑64/16 , EU:C:2018:117 , paragraph 44 and the case-law cited).

64That essential freedom from such external factors requires certain guarantees appropriate for protecting the person of those who have the task of adjudicating in a dispute, such as guarantees against removal from office (judgment of 19 September 2006, Wilson, C‑506/04 , EU:C:2006:587 , paragraph 51 and the case-law cited). Their receipt of a level of remuneration commensurate with the importance of the functions that they carry out also constitutes a guarantee essential to judicial independence (judgment of 27 February 2018, Associação Sindical dos Juízes Portugueses, C‑64/16 , EU:C:2018:117 , paragraph 45 ).

65The second aspect, which is internal in nature, is linked to impartiality and seeks to ensure that an equal distance is maintained from the parties to the proceedings and their respective interests with regard to the subject matter of those proceedings. That aspect requires objectivity and the absence of any interest in the outcome of the proceedings apart from the strict application of the rule of law (judgment of 19 September 2006, Wilson, C‑506/04 , EU:C:2006:587 , paragraph 52 and the case-law cited).

66Those guarantees of independence and impartiality require rules, particularly as regards the composition of the body and the appointment, length of service and grounds for abstention, rejection and dismissal of its members, in order to dispel any reasonable doubt in the minds of individuals as to the imperviousness of that body to external factors and its neutrality with respect to the interests before it. In order to consider the condition regarding the independence of the body concerned as met, the case-law requires, inter alia, that dismissals of its members should be determined by express legislative provisions (judgment of 9 October 2014, TDC, C‑222/13 , EU:C:2014:2265 , paragraph 32 and the case-law cited).

67The requirement of independence also means that the disciplinary regime governing those who have the task of adjudicating in a dispute must display the necessary guarantees in order to prevent any risk of its being used as a system of political control of the content of judicial decisions. Rules which define, in particular, both conduct amounting to disciplinary offences and the penalties actually applicable, which provide for the involvement of an independent body in accordance with a procedure which fully safeguards the rights enshrined in Articles 47 and 48 of the Charter, in particular the rights of the defence, and which lay down the possibility of bringing legal proceedings challenging the disciplinary bodies’ decisions constitute a set of guarantees that are essential for safeguarding the independence of the judiciary.

68If, having regard to the requirements noted in paragraphs 62 to 67 of the present judgment, the executing judicial authority finds that there is, in the issuing Member State, a real risk of breach of the essence of the fundamental right to a fair trial on account of systemic or generalised deficiencies concerning the judiciary of that Member State, such as to compromise the independence of that State’s courts, that authority must, as a second step, assess specifically and precisely whether, in the particular circumstances of the case, there are substantial grounds for believing that, following his surrender to the issuing Member State, the requested person will run that risk (see, by analogy, in the context of Article 4 of the Charter, judgment of 5 April 2016, Aranyosi and Căldăraru, C‑404/15 and C‑659/15 PPU , EU:C:2016:198 , paragraphs 92 and 94 ).

69That specific assessment is also necessary where, as in the present instance, (i) the issuing Member State has been the subject of a reasoned proposal adopted by the Commission pursuant to Article 7(1) TEU in order for the Council to determine that there is a clear risk of a serious breach by that Member State of the values referred to in Article 2 TEU, such as that of the rule of law, on account, in particular, of actions impairing the independence of the national courts, and (ii) the executing judicial authority considers that it possesses, on the basis, in particular, of such a proposal, material showing that there are systemic deficiencies, in the light of those values, at the level of that Member State’s judiciary.

70It is apparent from recital 10 of Framework Decision 2002/584 that implementation of the European arrest warrant mechanism may be suspended only in the event of a serious and persistent breach by one of the Member States of the principles set out in Article 2 TEU, determined by the European Council pursuant to Article 7(2) TEU, with the consequences set out in Article 7(3) TEU.

71It thus follows from the very wording of that recital that it is for the European Council to determine a breach in the issuing Member State of the principles set out in Article 2 TEU, including the principle of the rule of law, with a view to application of the European arrest warrant mechanism being suspended in respect of that Member State.

72Therefore, it is only if the European Council were to adopt a decision determining, as provided for in Article 7(2) TEU, that there is a serious and persistent breach in the issuing Member State of the principles set out in Article 2 TEU, such as those inherent in the rule of law, and the Council were then to suspend Framework Decision 2002/584 in respect of that Member State that the executing judicial authority would be required to refuse automatically to execute any European arrest warrant issued by it, without having to carry out any specific assessment of whether the individual concerned runs a real risk that the essence of his fundamental right to a fair trial will be affected.

73Accordingly, as long as such a decision has not been adopted by the European Council, the executing judicial authority may refrain, on the basis of Article 1(3) of Framework Decision 2002/584, to give effect to a European arrest warrant issued by a Member State which is the subject of a reasoned proposal as referred to in Article 7(1) TEU only in exceptional circumstances where that authority finds, after carrying out a specific and precise assessment of the particular case, that there are substantial grounds for believing that the person in respect of whom that European arrest warrant has been issued will, following his surrender to the issuing judicial authority, run a real risk of breach of his fundamental right to an independent tribunal and, therefore, of the essence of his fundamental right to a fair trial.

74In the course of such an assessment, the executing judicial authority must, in particular, examine to what extent the systemic or generalised deficiencies, as regards the independence of the issuing Member State’s courts, to which the material available to it attests are liable to have an impact at the level of that State’s courts with jurisdiction over the proceedings to which the requested person will be subject.

75If that examination shows that those deficiencies are liable to affect those courts, the executing judicial authority must also assess, in the light of the specific concerns expressed by the individual concerned and any information provided by him, whether there are substantial grounds for believing that he will run a real risk of breach of his fundamental right to an independent tribunal and, therefore, of the essence of his fundamental right to a fair trial, having regard to his personal situation, as well as to the nature of the offence for which he is being prosecuted and the factual context that form the basis of the European arrest warrant.

76Furthermore, the executing judicial authority must, pursuant to Article 15(2) of Framework Decision 2002/584, request from the issuing judicial authority any supplementary information that it considers necessary for assessing whether there is such a risk.

77In the course of such a dialogue between the executing judicial authority and the issuing judicial authority, the latter may, where appropriate, provide the executing judicial authority with any objective material on any changes concerning the conditions for protecting the guarantee of judicial independence in the issuing Member State, material which may rule out the existence of that risk for the individual concerned.

78If the information which the issuing judicial authority, after having, if need be, sought assistance from the central authority or one of the central authorities of the issuing Member State, as referred to in Article 7 of Framework Decision 2002/584 (see, to that effect, judgment of 5 April 2016, Aranyosi and Căldăraru, C‑404/15 and C‑659/15 PPU , EU:C:2016:198 , paragraph 97 ), has sent to the executing judicial authority does not lead the latter to discount the existence of a real risk that the individual concerned will suffer in the issuing Member State a breach of his fundamental right to an independent tribunal and, therefore, of the essence of his fundamental right to a fair trial, the executing judicial authority must refrain from giving effect to the European arrest warrant relating to him.

79In the light of the foregoing considerations, the answer to the questions referred is that Article 1(3) of Framework Decision 2002/584 must be interpreted as meaning that, where the executing judicial authority, called upon to decide whether a person in respect of whom a European arrest warrant has been issued for the purposes of conducting a criminal prosecution is to be surrendered, has material, such as that set out in a reasoned proposal of the Commission adopted pursuant to Article 7(1) TEU, indicating that there is a real risk of breach of the fundamental right to a fair trial guaranteed by the second paragraph of Article 47 of the Charter, on account of systemic or generalised deficiencies so far as concerns the independence of the issuing Member State’s judiciary, that authority must determine, specifically and precisely, whether, having regard to his personal situation, as well as to the nature of the offence for which he is being prosecuted and the factual context that form the basis of the European arrest warrant, and in the light of the information provided by the issuing Member State pursuant to Article 15(2) of the framework decision, there are substantial grounds for believing that that person will run such a risk if he is surrendered to that State.