[I am grateful to Robbie the Pict for drawing my attention to the following section in the Wikipedia article Lord Advocate:]
Calls for reform
In the Greshornish House Accord of 16 September 2008, Professors Hans Köchler and Robert Black said—
It is inappropriate that the Chief Legal Adviser to the Government is also head of all criminal prosecutions. Whilst the Lord Advocate and Solicitor General continue as public prosecutors the principle of separation of powers seems compromised. The potential for a conflict of interest always exists. Resolution of these circumstances would entail an amendment of the provisions contained within the Scotland Act 1998.
The judges of Scotland's highest court came to share this view. In a submission to the commission set up to consider how the devolution settlement between Scotland and the United Kingdom could be improved, the judges recommended that the Lord Advocate should cease to be the head of the public prosecution system and should act only as the Scottish Government's chief legal adviser. They noted various ways in which the Lord Advocate's roles had caused problems for the judicial system, including the ability "to challenge... virtually any act of a prosecutor has led to a plethora of disputed issues, with consequential delays to the holding of trials and to the hearing and completion of appeals against conviction."
The judges proposed three alternative solutions: stripping the Lord Advocate of responsibility for prosecutions, exempting the Lord Advocate from compliance with the European Convention on Human Rights, or changing the law on criminal appeals. While not specifically favouring any of the three, they noted that the third proposal was radical enough to "generate considerable controversy". Judiciary in the Court of Session (Just over half way down the list headed "Miscellaneous Submissions")