At present the lord advocate’s role as head of the systems of criminal prosecution and investigation of deaths is protected from modification by section 29 of the Scotland Act.

The SNP 2021 Holyrood manifesto set out plans to consult on whether the dual functions of the law officers, as head of the independent prosecutions service and principal legal advisers to the Scottish government should be separated.

The Scottish government has committed to review the role of the lord advocate by the end of the current parliament, the initial phase of which is to be informed by expert research.

A report is expected imminently. However, the Scottish Parliament lacks the powers to change the nature of the roles as this is reserved to Westminster and the bill would transfer the necessary powers to the Scottish Parliament.

Ms Cherry said: “The role and function of Scotland’s chief law officer is reserved to Westminster. The straitjacket of the Scotland Act has prevented the Scottish Parliament and Scottish government from modernising the post, as it might have done since 1999, by splitting the dual roles of providing independent legal advice to the government of the day and that of head of the prosecution service in Scotland. This would avoid any conflict of interest whether real or perceived.

“All major political parties in Scotland have called for a review of the role of the lord advocate, there is widespread support for splitting the roles and I trust that my bill will have cross party backing when it comes before the Commons.”

The vast majority of respondents to a poll conducted by Scottish Legal News in March 2021 voted in favour of splitting the role of the lord advocate into those functionally equivalent to an attorney general and director of public prosecutions.