Rishi Sunak is under growing pressure to bar Boris Johnson from standing as a Conservative candidate at the next election, as senior Tories accused the former prime minister and his allies of a coordinated attempt to derail the government. Amid anger at Johnson within the party over his explosive departure, in which he said he was only leaving Westminster “for now” and accused a cross-party committee of “egregious bias”, there is now a concerted push among senior Tories to ensure Johnson has no route back to the Commons for the foreseeable future. One senior member of the 1922 Committee of Tory backbenchers, a former backer of Johnson, said it was the clear view among colleagues that he should be blocked from standing for another Tory seat at the next election. “The pantomime has to end. He has to be stopped by whatever means and the sooner the better,” said the senior figure. Another grandee on the backbenches, who is close to Sunak and who used to support Johnson, added: “The way he has behaved in insulting the process of the House of Commons is disgraceful. He thinks he can just casually insult parliament. If he is allowed to stand again he will continue to undermine the government.” Writing in the Observer, former Tory deputy prime minister Michael Heseltine says Johnson’s angry resignation and threat of a return have “all the characteristics of a disaster turned into an opportunity”. He should not be allowed to run for the party again, Lord Heseltine says. “That is Boris’s basic problem,” he writes. “Words are designed to make his audience believe whatever they want to believe. There is no anchor to any discernible truth or sense of integrity. “To me it is inconceivable that in these circumstances he could stand as a Conservative member of parliament again. It is up to Conservative central office to affirm an official Conservative candidate. No doubt he will now go out into the world and make huge sums of money, writing history as he thinks it was conducted. But it will have little to do with the reality of the mess he left behind.” There has been wild speculation in Westminster over Johnson’s next move, with some suggesting he could even attempt to run in the Mid Bedfordshire byelection caused by the resignation of Nadine Dorries, one of his staunchest backers. However, Tory sources dismissed the idea as a non-starter. It comes as another close Johnson ally, Nigel Adams, triggered a third potentially damaging byelection by announcing on Saturday that he was stepping down with immediate effect. Sunak was already facing byelections in Johnson’s Uxbridge seat, which Labour are confident of winning, and Dorries’s constituency, which is being targeted by the Lib Dems. Some senior figures in Sunak’s team believe that the activities of a rump of MPs who remain fiercely loyal to Johnson are designed to cause maximum disruption. “It’s a Thelma and Louise moment, deciding to drive off the cliff together,” said a minister. Chris Bryant, the Labour chair of the Commons standards and privileges committee, who withdrew from the inquiry into Johnson and Partygate, says the ex-PM may now face further sanctions over the manner of his announcement on Friday. Also writing in the Observer, he says: “The committee may additionally conclude that his attacks on the committee were in themselves a contempt of parliament.” Bryant added that other sanctions should be considered: “The very least the house could do is refuse Johnson privileged access to parliament, with an ex-MP pass, for life.” Johnson quit as an MP on Friday night after being sent the verdict of the standards committee, which had been examining whether he misled MPs over Partygate. Members of the committee, which has a Tory majority, are set to gather on Monday to finalise the report and publish it soon after. It is understood that the report finds Johnson did mislead MPs and recommends a suspension from the Commons of more than 10 days – the bar for a recall petition that can trigger a byelection. According to an Opinium poll taken at the end of March, a majority of people said they believed Johnson should resign if the committee ruled against him over misleading MPS about Partygate. More than two thirds (69%) said they thought he should resign, while 64% thought he was lying in his testimony to the committee – something he vehemently denies. Party figures insisted on Saturday that the overwhelming response from MPs had been frustration at Johnson’s conduct. Tory MPs are furious that the departure of Johnson and his allies will torpedo Sunak’s attempts to restore order in the party. “His refuseniks will not let it lie so the damage to the party will be huge,” said one. “They won’t let Rishi succeed.” Morale among Conservatives has been sent tumbling by the new bout of infighting. Forty-four MPs have already announced that they will not contest the next election. Johnson’s Uxbridge seat, which had a majority of just 7,000 at the last election, looks likely to fall into Labour hands. The Lib Dems have already begun their assault on Dorries’s Mid Bedfordshire seat, which has a 25,000 majority. However, Lib Dem officials said they needed to secure a smaller swing than some of their other recent byelection successes. They began campaigning on Saturday and printed 40,000 leaflets to distribute to constituents. Some of those who worked with Johnson said that they could not see a way back for him within the next five years. “It’s over,” said a former ally. “Obviously never say never, but he’s gone. He always wants to maintain he’s a prince over the water. But it’s much harder to be a prince over the water without a position in parliament. His supporters are leaving. He could only get 20-odd votes on opposing the [Northern Ireland] Brexit deal. This is just a way of avoiding an exposure of the weakness of his position.”