Boris Johnson is not expected to announce further restrictions on Monday after he is briefed on the impact Christmas had on Covid infections and hospital pressures. The prime minister delayed any new cabinet summit on restrictions until after his regular data briefing with England’s chief medical officer, Prof Chris Whitty – expected to be knighted in the new year honours – and the government’s chief scientific adviser, Sir Patrick Vallance. Key evidence that the government will examine on Monday includes data on the length of stay in hospitals, the transition rates to ICU and new death figures. There is concern among some government figures about undeclared positive cases, including those who are asymptomatic but also those isolating after a lateral flow test whose results are not recorded by the NHS because they do not take a PCR test. Before Christmas, Johnson’s cabinet pushed back against new curbs, with key opponents including the transport secretary, Grant Shapps, the foreign secretary, Liz Truss, and the business secretary, Kwasi Kwarteng. However, cabinet sources said minds could change if there were compelling changes in the data. A source close to Shapps said: “Grant is pretty optimistic that we will not have to enter a full-blown lockdown post-Christmas but he is not dogmatic on the subject. “Some in the cabinet take their cue from him because he has no axe to grind and will opt for lighter or tougher measures purely on the available data.” A separate cabinet source said the positive data on the Omicron variant’s severity proved they had been right to hold out. A UK Health Security Agency analysis found those catching Omicron were 50-70% less likely to need hospital care compared with previous variants. “It was right that we didn’t rush last time given positive early data,” they said. A third cabinet minister said: “The data so far is still struggling to be persuasive of legal changes to be required.” Government sources have ruled out some of the most controversial restrictions, including school closures. The Times reported on Monday that weddings and funerals would also be exempt from any further curbs on large gatherings. Conservative MPs are expected to be fiercely resistant to any changes. One Tory MP, Sir Geoffrey Clifton-Brown, said the prime minister should “wait and see” what happens with Omicron in the coming days before taking a decision on further measures. The treasurer of the 1922 Committee of backbench Conservatives told Times Radio: “I think unless the data is very different to that which it was before Christmas, the prime minister would do well just to wait and see what happens in the next few days, because by next week we will have a very clear idea of whether these large number of infections are going to translate into hospital cases. “But, at the moment, I would urge caution because of the damage to the economy and the damage to individuals by locking them down unnecessarily.” Asked whether he was concerned that England was “out of step” with the rest of the UK in terms of Omicron restrictions, the Cotswolds MP replied: “I think it is the other way round. “I think the principalities are out of step with England. I think they have been overly cautious. I think they are doing more damage to their economies than they need to. I think they are doing more damage to people’s liberties than they need to – I just don’t think the evidence, unless the data coming out today looks very different, is there for any further measures.” He said should Johnson choose to strengthen the measures required to tackle Omicron, it would “not be a cop-out at all” to introduce them as guidance rather than written into law, adding: “I think that would be a very sensible way to go forward.”