[37] The appellant presented his central argument on the basis that there had been an infringement of his Article 6 right to a fair trial rather than that the statements had been taken unfairly by the police and were therefore inadmissible at common law. He submitted that the trial judge had been in error in holding that, as at Tuesday, 6 May, the police did not have reasonable cause to suspect the appellant of a particular offence and that they would not have been able to inform him of the general nature of that offence. This error was demonstrated by the fact that there had been no material change in circumstances between that date and the time when the appellant's status had been officially changed. It was accepted that the crucial statement was the first one, taken over the period from midnight on Wednesday, 5 May, through to 11 am on Thursday, 6 May.
[38] Although the dividing line beyond which a witness became a suspect was a "fine one", and general principles of fairness had a bearing upon it, nevertheless the appellant had been a suspect by the time the first statement had been taken. That was so even if the general nature of the offence of which he was suspected may have been rather more vague than the eventual libel. The appellant could have been detained for abduction in terms of section 14 of the 1995 Act, where the requirement was only to specify "the general nature of the offence". Although it was accepted that the appellant had agreed to assist the police, that consent did not relieve the police of the obligation to caution a suspect before questioning him. It was not argued at the appeal that the circumstances involved such constraint that the appellant ought to have been given access to a lawyer.
[39] Contrary to the trial judge's views, the whole circumstances ought to have been considered, with the benefit of hindsight, when deciding whether someone had become, or ought to have been treated as, a suspect (Ambrose v Harris (supra), Lord Hope at para 62). On such a consideration, a person may become a suspect, and thus be entitled to the rights implicit in Article 6, at least to the extent of a caution being required, even if there was insufficient information to justify detention (ibid, Lord Hope at paras 67-69). There were a number of significant factors which pointed towards the appellant being regarded as a suspect, not least the involvement of CID officers at an early stage. Leaving aside the immediately known facts, the early investigation quickly reduced the likelihood of any legitimate explanation existing for the disappearance of the deceased. The circumstances were suspicious from a very early stage. It was necessary to consider the realities of the situation (Artico v Italy (1981) 3 EHRR 1 at para 33).
[40] Ambrose v Harris (supra) made it clear that the rights implicit in Article 6 became active in stages. The first of these stages involved the caution. That stage occurred as soon as Article 6 became engaged. It could occur before the point of detention or arrest, since Article 6 afforded rights to those who had been "charged" with a criminal offence (Imbrioscia v Switzerland (1994) 17 EHRR 441 at para 36; Zaichenko v Russia (supra) at para 42; and Serves v France (1999) 28 EHRR 265 at paras 40-42). The word "charge" had been defined as being "the official notification given to an individual by the competent authority of an allegation that he has committed a criminal offence" and this corresponded to the point when "the situation of the suspect has been substantially affected" (Deweer v Belgium (1980) 2 EHRR 439 at para 46; Eckle v Germany (1983) 5 EHRR 1 at para 73; Burns v HM Advocate 2010 SC (PC) 26). A substantive, rather than a formal approach, was required (Subinski v Slovenia, ECtHR, unreported, 18 January 2007, (no. 19611/04), at paras 62-63; Foti v Italy (1982) 5 EHRR 313 at para 52). A suspect's position was substantially affected as soon as the suspicion against him was being seriously investigated and the prosecution case compiled (Ambrose v Harris (supra) Lord Hope at para [62]). A person was the subject of a "charge" when a preliminary investigation had been opened and the person, although not under arrest, had officially learned of the investigation or had begun to be affected by it. The relevant moment may be the first interrogation, or interview, by the police (Howarth v United Kingdom (2000) 31 EHRR 861, at para 20; Martins and Garcia Alves v Portugal, ECtHR, unreported, 16 November 2000, (no. 37528/97), at paras 19-20; Kangasluona v Finland, ECtHR, unreported, 20 January 2004, (no. 48339/99), at para 26; and Yankov and Manchev v Bulgaria, ECtHR, unreported, 22 October 2009, (no. 27207/04), at paras 18 and 24).