Many provisions of the European Convention on Human Rights refer to the ‘law’ of the Member States, or to the ‘lawfulness’ of their actions. A random selection includes Article 5, paragraph 2 ECHR (listing the circumstances in which limitations to the right to liberty of person are ‘lawful’), and Article 7, paragraph 1 ECHR (requiring penalties for criminal offences to be prescribed ‘by law’).
Since the earliest stages of its activity, the Strasbourg Court has developed an autonomous notion of ‘law’, applying to the interpretation of all these provisions. The term is autonomous on two levels. First, when the Court verifies the existence of a domestic legal basis, it is satisfied by a ‘substantial notion’ of law. Second, the Court requires the law to comply with qualitative standards.  Thus, in the ECHR system, ‘law’ is ‘a concept which comprises written as well as unwritten law and implies qualitative requirements, notably those of accessibility and foreseeability’.
The autonomous notion of ‘law’ developed by the ECtHR underpins its understanding of legality. In the ECHR system, legality means that an accessible and foreseeable provision of (written or unwritten) law must regulate the actions of the Member States, whenever they interfere with the Convention rights and freedoms.
This understanding has notable implications, analysed below with reference to the Strasbourg case law.
In 2000, the Court delivered its judgement in the case of Mr Baranowski, a Polish national who had been held on remand after the expiry of the time limit indicated by the detention order. The Polish law did not state the maximum length of detention on remand. Mr Baranowski thus complained that his deprivation of liberty had not been based on a ‘law’ of adequate foreseeability.
The European Court of Human Rights showed little interest in the absence of a domestic law. Its attention focused, instead, on assessing ‘whether domestic law itself is in conformity with the Convention’. The Court determined that the relevant Polish legislation did not satisfy the test of ‘foreseeability’, thereby, finding a violation of the applicant’s right to liberty of person. The same rationale was subsequently applied to other, similar judgments, the latest and most famous being that involving Ms Tymoshenko, the former prime minister of Ukraine.
In 2009 the Court delivered its judgment in the case of Liviik v Estonia. The case originated from an application concerning the Estonian offence of ‘misuse of official position’. The offence had been inherited from the former Sovietic legal system: thus, the domestic case law shaping the offence had developed within an entirely different economic system.
Mr Liviik applied to the European Court of Human Rights, alleging that his sentence had been based on an ‘unclear and incomprehensible (…) law’ and had thus had violated Article 7, paragraph 1 ECHR. The European Court, having analysed the background against which the offence had been developed, concluded that the interpretation and application of the domestic law was not of the quality required under the Convention in terms of clarity and foreseeability.
A similar judgement followed in 2012. It related to the application of Mr Alimuçaj, an Albanian citizen who had been sentenced to twenty years’ imprisonment for deception. His conviction was based on a new calculation system, and on the grounds of a new law attaching criminal consequences to the process of loan-taking. Mr Alimuçaj applied to the European Court complaining of the retrospective application of a heavier penalty and of the lack of a legal basis for his conviction. The Court dismissed his second claim and only considered whether, at the time that the offence was committed, there was ‘interpretive case law which would satisfy the foreseeability test’ with regard to the sentence of twenty years’ imprisonment. The Court concluded that, at the time the applicant had committed the offence, he could not have reasonably foreseen the penalty: thus, a violation of Article 7, paragraph 1 ECHR was found.
In 2013, the Court rendered its judgment in the case of Mr Vyerentsov, a Ukrainian national who had been arrested for taking part in a peaceful demonstration in Ukraine. He had been sentenced for breach of the demonstration procedure: however, the Ukrainian law was silent on the elements of this procedure. The European Court did not focus its attention on the inexistence of a national law and instead determined that the absence of clear indications as to the rules under which a demonstration could be organised rendered the national law unforeseeable. Thus, the restriction to the applicant’s right to peaceful assembly had not respected the qualitative standards required by the Convention notion of ‘law’.
The case law above exemplifies the understanding of legality adopted by the Strasbourg Court.
In all cases, the Court tends to focus more on the lack of ‘foreseeability’ of the domestic law, than on the lack of a national legal basis. In both Baranowski and Vyerentsov the Court, confronted with a lacuna, did not consider the lacuna in itself a violation of the Convention: the lacuna was deemed to cause a lack of ‘foreseeability’ in the national law.
The origins of this tendency are probably rooted in the broad definition of law promoted by the Court. Indeed, the Court considers as valid sources of law every ‘enactment in force as the competent courts have interpreted it’. For this reason, it is uncommon for the Court to be faced with the total absence of a national legal basis. The Court is usually confronted with national laws not complying with the qualitative requirements of accessibility and foreseeability, and it has thus developed a well-assessed body of case law based on this assumption.
This becomes particularly problematic in the field of criminal law. According to the autonomous notion of ‘law’ elaborated by the Strasbourg Court, the judicial creation of criminal offences is conceivable. The only limitation emanating from the ECHR system is that the criminal (written or unwritten) law must be developed and applied in a way that is ‘consistent with the essence of the offence’ and ‘reasonably foreseeable’ to its addressee. The Alimuçaj and Liviik cases are lucky examples of the positive consequences of this approach. However, this position also bears potentially dangerous consequences. ‘Consistency with the essence of the offence’ makes the evaluation of legality easily dependent on the nature of the offence under review. ‘Foreseeability’, on its part, is read by the Court as a subjective requirement. Consequently, the ‘number and status’ of those to whom the law is addressed is a central element of the Court’s evaluation of legality.
By making legality dependent on elements such as the content of the instrument at issue, the field it is designed to cover and the number and status of those to whom it is addressed, this notion of legality allows for the existence of vague laws. What it worst, it carries the risk of discrimination and of the retrospective application of criminal law. Indeed, when an offence consists of behaviour which is ‘naturally’ perceived to be criminal (e.g. rape or murder), the Court is more prone to assess the foreseeability of changes in the law, even though they are unfavourable to the accused. However, in all democratic legal systems, one of the essential desiderata of legality is the non-retroactivity of the criminal law. For this reason, the position developed by the Strasbourg Court towards legality should be handled with care when transposed into national legal orders.
 G LAUTENBACH, The Rule of Law, 112
 The Sunday Times v UK (no 1), par 49
 C.R. v UK (1995) Series A no 335-C, par 33
 Baranowski v Poland ECHR 2000-III
 Baranowski v Poland, par 43
 Baranowski v Poland, par 51
 Baranowski v Poland, par 55
 Kawka v Poland App no 25874/94 (ECtHR, 9 January 2001); ECtHR, case of Yeloyev v Ukraine App no 17283/02 (ECtHR, 6 November 2008); Farhad Aliyev v Azerbaijan App no 37138/06 (ECtHR, 9 November 2010)
 Tymoshenko v Ukraine App no 49872/11 (ECtHR, 30 April 2013)
 Liivik v Estonia App no 12157/05 (ECtHR, 25 June 2009)
Alimuçaj v Albania, App no 20134/05 (ECtHR, 7 February 2012)
 Vyerentsov v Ukraine, App no 20372/11 (ECtHR, 11 April 2013)
 Vyerentsov v Ukraine, par 54 and 67
 Huvig v France (1990) Series A no 176-B, par 28
 G. v France (1995) Series A no 325-B, par 34
 Groppera Radio AG and Others v Switzerland (1990) Series A no 173
 Eg: S.W. and C.R. v UK (1995) Series A nos 335-B and 335-C, Streletz, Kessler and Krenz v Germany, ECHR 2001-II