The right to legal advice was central to R v Taylor, 2014 SCC 50 (18 July 2014). The defendant had requested legal advice but this request was not acted on during the collection of a blood sample which was of central importance on an alcohol-related driving offence. On conducting the balancing exercise in accordance with R v Grant (discussed here on 19 July 2009) the Court held that the improperly obtained evidence was inadmissible.
The right to legal advice is closely associated with the right to silence. A motive for refusal of access to a lawyer, it may be reasonably be conjectured, could be that the police do not want the suspect to exercise the right to silence. And the right to silence is of fundamental importance: it is a corollary of the obligation on the prosecutor to prove the charge, and of the need to do so without the assistance of the defendant.
The right to legal advice has previously been the subject of commentary here: see Cadder v HM Advocate  UKSC 43 (here on 27 October 2010), R v Sinclair  SCC 35 (here on 15 October 2010), Salduz v Turkey  ECtHR 1542 (here on 3 December 2008).
The central issue highlighted in those comments is whether a breach of the right to legal advice raises fair trial issues, in which case a balancing exercise is not appropriate (but an exclusionary rule is), or whether it raises issues of public policy, where balancing of competing interests is appropriate.
It is easy to forget history and to say that the issue of the admissibility of evidence obtained in breach of the right to legal advice is an issue of policy. The Birmingham Six abuses of police power, and the manufacture of false confessions, came as a shock to British justice, and drove home the importance of the right to silence and the vulnerability of people who are held in custody.
In his wonderful article in The London Review of Books, vol 15 no 21 (4 November 1993) “A sewer runs through it”, Alastair Logan (a solicitor whose clients included the Guildford Four and the Maguire Seven) noted that research presented to the Royal Commission on Criminal Justice
“shows that 42 percent of those who were arrested and detained in police stations during the currency of the Commission were educationally subnormal or of borderline intelligence; another 7 percent were suffering from defined mental illnesses. The average IQ of detained persons was 82. One third were intellectually impaired, and 35 percent were not in a normal mental state due to extreme distress, mental disorder or drugs. Twenty percent were suffering from an unusually high level of anxiety and distress. About 20 percent required the assistance of an adult to safeguard them and their rights, though the police identified only 4 percent of that number as requiring such protection. The police commonly failed to recognise that detained persons suffering from depression were vulnerable. There is no systematic training available to police officers to enable them to identify vulnerable suspects or mental disorder. The removal of the right to silence attacks the vulnerable and the disorientated, who massively outnumber the terrorists and the professional criminals, in or out of uniform.”
It is very easy, in cases like Taylor where the alleged offending is not of the most serious kind, for courts to conclude that a balancing exercise favours exclusion of evidence obtained in breach of the right to legal advice. Indeed, in Taylor the Court was not concerned to explore what advice the defendant could have been given , or in what way absence of legal advice may have prejudiced his defence. For more serious allegations the balancing exercise may well include such considerations. Yet it is when being held in custody on more serious allegations that a person will be most in need of the protection of the right to legal advice, and a court would have to consider whether use of evidence improperly obtained from a vulnerable defendant really promotes respect for the law.