‘In the name of God, go’: Tory fury spills over as Boris Johnson clings on

Boris Johnson has faced a defection and a demand to quit from one of his most senior MPs during a dramatic day in Westminster, with even allies of the prime minister warning the current situation cannot go on.

David Davis caused shockwaves when he told Johnson in the Commons: "In the name of God, go." Less than an hour earlier, Christian Wakeford, the MP for Bury South, quit the Conservatives and joined Labour in fury at the Downing Street parties scandal.

The prime minister vowed to battle on in No 10 and his supporters insisted he now had the breathing space for a fightback, with many MPs awaiting the outcome of the Sue Gray inquiry.

But Johnson faces a growing clamour from Tory backbenchers to buy their support in any confidence vote by ditching a £12bn-a-year tax rise this spring. National insurance contributions are due to increase from April to fund health and social care and any U-turn could risk a showdown with the chancellor, Rishi Sunak.

Johnson managed to get through the day without a confidence vote being triggered. Tory MPs estimated that as many as 30 letters may have been submitted of the 54 required, with more expected to come in after Gray, a senior civil servant, delivers her finding on alleged rule-breaking in Downing Street next week.

The Guardian understands that members of the 1922 Committee of backbenchers are looking at shortening the period where a leader is immune from another vote of no confidence from 12 months to six. The same move was considered when Theresa May faced a no confidence ballot in December 2018 but survived.

The rebellion has so far been led publicly by disillusioned 2019-intake MPs worried about the plunge in support in their seats. But sources said the next wave of letters was likely to come in from "One Nation" Conservatives from the centrist wing of the party if the Gray report is sufficiently damning of Johnson's conduct.