A phrase frequently uttered by a suspect arrested by the police is: “I ain’t saying nothing until I’ve seen my brief.” Unless, that is, the arrest has taken place in Scotland.

The law in Scotland allows the police to detain a person for six hours without access to a lawyer. After six hours, the detained person must be arrested and charged, at which point they are entitled to see a lawyer, or they must be released. During those six hours, the police can interview their suspect and the procurator fiscal can then rely on the interview at trial to support the other prosecution evidence. If a person confesses to a crime in interview, the jury will be entitled to hear it unless their advocate can show that the police obtained the confession by duress or it would be otherwise unfair, such as when a person is drunk or of unsound mind.

The European court of human rights considered the fairness of this in an application brought against Turkey at the end of 2008 by a juvenile defendant named Salduz. The Strasbourg court held that the right to a fair trial required access to a lawyer to be provided from the first interrogation of a suspect by the police, unless there were compelling reasons to restrict the right. It concluded that the rights of the defence would in principle be irretrievably prejudiced where incriminating statements made without access to a lawyer were used for a conviction. The decision has been reiterated in successive cases before the court from Turkey, Russia, Ukraine, Poland and Cyprus.

The UK supreme court is presently hearing an appeal from Scotland in Cadder v Her Majesty’s Advocate on the application of the Salduz principle in Scotland.

Seven supreme court justices are considering the issue. Their decision will have significant ramifications for thousands of prosecutions pending in Scotland, and indeed many thousands of convictions already secured where confession evidence of this type was used at trial.

The Lord Advocate will be represented, as the Scottish minister responsible for the prosecution, with interventions from the recently appointed Lib Dem Advocate General, Lord Wallace, and human rights and law reform organisation Justice.

The advocates will assert that the Scottish system, considered as a whole, allows a fair trial to take place. But Peter Cadder argues that he did not receive a fair trial, and Justice considers that the cases before the Strasbourg court have shown similar systems to that of Scotland ? the opportunity for legal representation at trial and to argue for evidence to be excluded ? yet they have still fallen foul of Article 6.

A lawyer not only prevents the local scoundrel’s recollection of events from being assisted by the brick wall of the interview room (see the reminiscence of the Lord Chief Justice for the Judicial Studies Board lecture on 17 March), something that has hopefully now been confined to television dramas such as Ashes to Ashes. A lawyer crucially ensures that a suspect understands the allegations being made against them, whether they have a defence and how the system works.

The first police interview is the most critical part of a criminal case for a defendant, who is still supposed to be treated as innocent until they are proven guilty by the crown, not themselves. We think that the time has come for Scotland to catch up with England, Wales and Northern Ireland, and jurisdictions all over the world that recognise access to a lawyer as a fundamental right. We will see what the supreme court makes of it this week.

Jodie Blackstock is a barrister and senior legal officer in EU justice and home affairs at Justice. She is junior counsel, together with Aidan O’Neill QC, Tony Kelly and Herbert Smith, in Cadder v HM Advocate.  This post originally appeared in Guardian Law.

[Update] JUSTICE has helpfully provided us with a copy of its Intervention in the case of Cadder v HM Advocate, for which we are grateful.  We would be pleased to post copies of the Written Cases of the Appellant and the Respondent if we are provided with them.