Labour has launched a proposal to grant a cross-party select committee emergency powers if Boris Johnson fails to appoint a new ethics adviser.
It comes after the prime minister’s ethics adviser Lord Geidt quit last week, saying he “could not be party to advising on potential law breaking”.
Mr Johnson‘s official spokesperson has said there were no plans to replace Lord Geidt.
MPs will vote on Tuesday on whether the Public Administration and Constitutional Affairs Select Committee (PACAC) can appoint its own independent adviser on ministerial code breaches and initiate its own investigations if the role remains unfilled.
Labour deputy leader Angela Rayner said: “The prime minister has driven both of his own hand-picked ethics advisers to resign in despair in just two years, leaving an ethical vacuum in Downing Street.
“Labour will put Number 10 in special measures to prevent this prime minister running roughshod over the rules, dodging accountability, and degrading standards in public life.
“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.
“Labour’s proposal would ensure that a cross-party group of MPs is given powers to step in and monitor this rogue prime minister’s behaviour until a new, genuinely independent adviser is confirmed.
“This vacancy must not only be filled, but the role urgently reformed as the Committee on Standards in Public Life has concluded. It’s time for Conservative MPs to stop propping up this disgraced prime minister and back Labour’s plan to clean up politics.”
Lord Geidt became the second independent adviser to resign under Mr Johnson, saying the prime minister had left him in an “impossible and odious position”.
Prior to standing down last week, he admitted he had considered resigning over Mr Johnson’s response to his partygate fine for breaking COVID-19 rules.
Explaining to the prime minister why he was leaving, Lord Geidt said he believed “by a very small margin” that it was possible “to continue credibly as independent adviser” after partygate.
In his resignation letter, Lord Geidt said he had been asked to offer a view on “measures which risk a deliberate and purposeful breach of the ministerial code”.
“This request has placed me in an impossible and odious position,” he said.
“The idea that a prime minister might to any degree be in the business of deliberately breaching his own code is an affront.”