A committee of MPs has concluded that the attorney general should no longer combine the roles of politician and legal adviser to the government.
The issue has been hotly debated within government in the past year, with the current attorney Baroness Scotland of Asthal reported to be at odds with justice secretary Jack Straw.
Cases such as former attorney Lord Goldsmith's advice on the legality of the Iraq war and the government's decision to stop a corruption investigation into arms sales to Saudi Arabia have brought under the spotlight the post's combined cabinet and legal roles.
And the Commons justice committee said on Tuesday that the forthcoming constitutional renewal bill should be clear about how the roles should divide.
It said in a new report that, in order to increase public confidence that legal decisions were not made under political pressure, the attorney should not be a minister.
The committee also expressed concern that legislation as currently drafted would actually increase the power of ministers.
"The draft bill fails to achieve the purpose given to constitutional reform by the prime minister; it gives greater power to the executive and does not sufficiently increase transparency," the MPs said.
Committee chairman Sir Alan Beith added: "The main areas that concern the public about the attorney general's role arise from fears that a politician, sitting in cabinet and with the traditional collective responsibility for the decisions of that cabinet, may not be independent when acting as legal adviser on major political decisions, or making the decision about ending prosecutions, or in some cases investigations.
"Even if we have been able to trust individuals who have held the role to 'wear different hats' and keep these two roles separate for themselves, it can't be right for that to be the constitutional position.
"The legal powers of the role, the powers to bring or intervene in legal proceedings, and of being chief legal adviser to the government, could surely all be better performed by a non-political office holder.
"The attorney general's ministerial role, involving political responsibility for prosecution policy, should remain with a political office holder.
"This Bill has been called more of a 'constitutional retreat bill' than a constitutional renewal bill and on this issue certainly we feel that it fails to achieve the purpose given to constitutional reform by the prime minister: it gives greater power to the executive and it does not add to transparency."
24 June 2008