Labour is calling a vote to give MPs powers to hold ministers to account if Boris Johnson’s ethics chief is not replaced.

The party’s proposals, which will be put to the Commons on Tuesday, would grant a parliamentary committee the right to initiate its own investigations into potential breaches of the ministerial code, led by a new specialist adviser.

It comes after Lord Geidt stood down last week, saying the Prime Minister had put him in an “impossible and odious position” when he asked for his advice on maintaining tariffs on Chinese steel in a deliberate breach of the UK’s obligations in international law.

He had previously made clear his “frustration” at Boris Johnson’s response to being fined by police for a breach of Covid rules when he attended a gathering in No 10 to mark his 56th birthday.

The Prime Minister has so far failed to commit to appointing a successor.

Downing Street has accepted Lord Geidt fulfilled a “vitally important” function advising on the ministerial code of conduct but said Mr Johnson was reviewing the position and could abolish it.

Labour’s proposals would give powers to the Commons Public Administration and Constitutional Affairs Select Committee (PACAC) to appoint an independent adviser on possible breaches of the code and initiate its own investigations, if the role remained unfilled for two months or more.

The new “adviser on ministers’ interests” would advise the committee on the effectiveness of the ministerial code and on any potential violations, the party said.

They would need to consider any possible breaches referred to them by the PACAC, and may also initiate their own investigations.

Angela Rayner, Labour’s deputy leader, warned of an “ethical vacuum in Downing Street”.

“Labour will put No 10 in special measures to prevent this Prime Minister running roughshod over the rules, dodging accountability and degrading standards in public life,” she said.

“While this sleaze-ridden Prime Minister is propped up in office by Conservative MPs, the Government is totally unable to tackle the cost-of-living crisis facing the British people.”

She said the ethics chief’s vacancy “must not only be filled, but the role urgently reformed”.

“It’s time for Conservative MPs to stop propping up this disgraced Prime Minister and back Labour’s plan to clean up politics,” she added.