A joint committee of MPs and peers has failed to come to an agreement over the role of the attorney general.
The report on Thursday from a special committee set up to look at the issue was split into majority and minority factions over the law officer's continuing legal and political role.
A majority of 11 concluded that the government was right to say that the attorney general should retain both a ministerial seat and a say in major prosecution decisions.
But a minority of six said this was "letting the government off the hook".
The controversial government plans are contained in the Draft Constitutional Renewal Bill.
Ministers want to reduce the power of the attorney in certain areas but allow the post-holder - currently Baroness Scotland - to remain in government and have a say in some cases, such as those relating the national security.
And the majority report said it was right that the government retains this "nuclear option".
But the cross-party minority group, led by Liberal Democrat Lord Tyler, claimed the legislation was a "ragbag of retreats" on the government's aim of separating the judiciary from the executive and Parliament.
And he pointed out that two other parliamentary committees had also come to the same conclusion.
"In particular, this bill will fail to rekindle public confidence in the sullied office of attorney general since it ducks the opportunity to separate her legal and political functions," Lord Tyler said.
"Other members of the joint committee may be prepared to stand by while the government prevents essential separation of powers in the British constitution.
"But we are determined that two unanimous reports of Commons select committees - each with a government majority - should not be ignored when Parliament examines this legislation."
Dods Parliamentary Communications Ltd