On 10 September 2007, the trial of Angus Sinclair for the murder of two women in October 1977, which became known as the World's End murders, collapsed. At the close of the prosecution's case, the presiding judge, Lord Clarke, upheld the defence submission that there was no case to answer and the case was thrown out without the defence having to lead any evidence. This outcome has reignited debate surrounding two important aspects of the criminal law; first the Crown's right of appeal in criminal cases and secondly, the rule against double jeopardy.

Following the collapse of the trial, the Lord Advocate, Elish Angiolini, appeared before the Scottish Parliament to discuss the trial and in particular, the Crown's handling of the case. During the question and answer session, the Lord Advocate acknowledged that if the Crown had a right to appeal the judge's decision, it would have done so in this case. As the law currently stands in Scotland, the Crown does not have that right.

Prior to the Lord Advocate's appearance, the First Minister, Alex Salmond, had indicated that he was considering the introduction of such a right as part of a wider review of the criminal justice system. He confirmed that this review would also look at the rule against double jeopardy – that is, the rule that prevents a person who has been acquitted or convicted of an offence being subsequently charged with the same offence. This position is in keeping with the decision of the Scottish Parliament, following a debate on the double jeopardy issue in February this year, in which MSPs voted to consider the issue in the context of the wider criminal justice system.

The Law Commission in England and Wales looked into both the Crown's right of appeal and the double jeopardy rule in England and Wales several years ago. It recommended that the law relating to double jeopardy be reformed only in relation to murder cases to allow the Court of Appeal to quash an acquittal where there is reliable and compelling new evidence of guilt and a retrial would be in the interests of justice. Amongst other recommendations, the Law Commission's report also suggested that the Crown should have the right to appeal against a ruling by the judge at the close of the prosecution's case that there is no case to answer. The Criminal Justice Act 2003 implemented the recommendations and now allows retrials if there is "new" and "compelling" evidence. However, the Act went further than the Law Commission's recommendations and in addition to cases of murder, the provisions also apply to certain other serious crimes.

Whether this approach will eventually be applied to Scotland remains to be seen but it will surely be the subject of much debate. At least part of that debate will almost certainly focus on the human rights implications of removing the rule against double jeopardy in Scotland. Removing the rule against double jeopardy could be seen as interfering with Article 6 ECHR - the right to a fair trial. More specifically, paragraph 1 of Article 4 of Protocol 7 to the ECHR states that "no one shall be liable to be tried or punished again in criminal proceedings under the jurisdiction of the same State for an offence for which he has already been finally acquitted or convicted in accordance with the law and penal procedure of that State." While this protocol has yet to be ratified in the UK, the Government has confirmed its commitment to do so in the future. However, paragraph 2 of that article specifically states that the rule against double jeopardy may be disapplied so long as it is "in accordance with the law and penal procedure of the State" where there is "evidence of new or newly discovered facts" or "a fundamental defect in the previous proceedings".

Whatever the future holds for the law in Scotland, it seems certain that there is a lot to be discussed.