Sajid Javid has fuelled Tory anger over the government’s plan B Covid measures before votes that are expected to mark the biggest rebellion of Boris Johnson’s premiership. The health secretary was accused of “shifting the goalposts” by confirming that in the new year Covid passports would require proof of three jabs – not two – or a negative test. About 80 Conservative backbenchers have already signalled their opposition to Covid certificates before Tuesday’s vote, with cabinet ministers including Michael Gove deployed to phone colleagues and get them back on side to reduce the embarrassment facing Johnson. The plan B votes are expected to pass, but only thanks to Labour support. To tackle the spread of the Omicron coronavirus variant, Javid announced in parliament on Monday that to qualify for a Covid pass, people would need proof of a recent negative test result or three jabs, rather than two. He said the change would come into force “once all adults have had a reasonable chance to get their booster jab”. The move is part of a drive to boost inoculation levels and increase the safety of large events and nightclubs, where the passes will be needed. So far, 89% of those eligible in the UK have had a first jab, but the figure falls to 81% for second doses and 41% for the booster. Despite Javid’s insistence that many of his own MPs were rallying against a “misleading description of what the government is proposing”, he was met by growing hostility. Andrea Leadsom, a former cabinet minister, quoted a constituent who hit out at “intrusive and incoherent government regulations,” while one-time Tory leader Iain Duncan Smith admitted being “concerned about the mixed and heavy messaging coming from the government”. Mark Harper, chair of the Covid Recovery Group, also said it was “not acceptable to keep governing this country by decree” and hit out at “late night television addresses” after Johnson’s statement on Sunday evening. Javid stressed that plan B measures – which include working from home and more mask-wearing as well as Covid passports – were necessary because hospitalisations and deaths lag two weeks behind cases, and would “dramatically increase” in the run-up to the new year. The planned change to vaccination requirements for a Covid passport galvanised Tory anger on the eve of votes on plan B, one of which is expected to focus on the certificates. Several Conservative MPs accused the government of moving the goalposts. One told the Guardian: “I think it’ll strengthen the resolve of some of the 80 opponents who are flaky, and win over more … It’s ridiculous, because there is no chance that everyone is going to get their booster by the end of this month – that’s just way out in the stratosphere as a concept.” The MP said if at least 80 Tories rebelled on Tuesday, that would be Johnson’s effective Commons majority. They added: “These restrictions are the gateway drug to more serious restrictions down the line. I think we’ll be on plan X, Y or Z by Christmas.” Another backbencher said “scare stories” about further restrictions beyond plan B had “actually had the opposite effect on rebels, who mainly see the reintroduction of restrictions as a slippery slope”. Among the growing number of Tory MPs who signalled that they would oppose some of the plan B measures were many of the 2019 intake. Those who declared their opposition on Monday included Tom Hunt, Robbie Moore and Shaun Bailey. Labour will back all the plan B measures, meaning their approval is all but guaranteed. Wes Streeting, the shadow health secretary, accused the government of “rowing back on the target set yesterday” after Johnson said all adults would be able to get a booster by 31 December, while Javid said they would receive an “offer” by the end of the year to book their third jab. Streeting said: “The prime minister has got to learn to be straight with people, because he is undermining public trust and confidence in the government and public health measures at a critical time.” Further Covid restrictions were also introduced in parliament on Monday, with Tory MPs’ Christmas drinks reception cancelled by the House of Commons Commission. Banqueting, tours and education activities were all cancelled with immediate effect.