Nearly 100 Tory MPs on Tuesday voted against new coronavirus restrictions in the largest ever rebellion against Prime Minister Boris Johnson from within his own party as he battles to prevent the Omicron variant spiralling out of control.

The evening vote in the House of Commons was the largest backlash Johnson has faced from within his own ranks since an emphatic election victory in December 2019, putting him under further pressure after a string of recent scandals.

The new restrictions were still passed by the MPs as a whole, but 97 Tories defied the party line and voted against a new rule requiring Covid passes for entry to venues such as nightclubs and sports stadiums.

This was far higher than predicted and prompted suggestions that Johnson could face a leadership challenge unless he appeases the rebels.

Tory opponents argued that such measures undermine public freedoms, while the main opposition Labour party overwhelmingly supported the new restrictions.

Boris Johnson's own MPs say they will rebel against the government's new coronavirus restrictions
Boris Johnson's own MPs say they will rebel against the government's new coronavirus restrictions UK PARLIAMENT via AFP / JESSICA TAYLOR

The Tories have an 80-seat majority in the 650-seat House of Commons.

Smaller numbers of Tory MPs (61) opposed measures to require state health care and social care staff to get vaccinated by April 2022, while 38 voted against making masks mandatory in theatres and cinemas.

The evening vote came after Health Secretary Sajid Javid told MPs that Omicron was "a grave threat" and even though hospital admissions were still low, action was needed.

"They are measures that I think the situation demands because when the facts change, our response must change too," he said.

"There really is no time to lose," Javid added, noting scientists have predicted the true figure of those already infected in Britain could be as high as 200,000 a day.

Defeat or a significant cut in the Tory majority in a by-election in the North Shropshire constituency vacated by Owen Paterson could put Johnson under added pressure
Defeat or a significant cut in the Tory majority in a by-election in the North Shropshire constituency vacated by Owen Paterson could put Johnson under added pressure AFP / Tolga AKMEN

But he confirmed that 11 countries, most of them in southern Africa, would be taken off the UK's so-called travel red list -- barring most arrivals -- as it was now "less effective" in stopping the spread.

Johnson, who has warned of a looming "tidal wave" of Omicron cases that could overwhelm hospitals, said Monday at least one person had died after contracting it.

The country recorded nearly 60,000 new Covid-19 cases in the 24 hours to Tuesday -- one of its highest daily tallies of the pandemic -- as the variant became the dominant strain in London.

The British government wants to introduce new restrictions to slow the Omicron variant's spread
The British government wants to introduce new restrictions to slow the Omicron variant's spread AFP / John SAEKI

Several shows in the capital's West End theatre district, including "The Lion King", have been forced to cancel performances following outbreaks among cast and crew.

Meanwhile, Manchester United's football match at Brentford on Tuesday was postponed as the English Premier League reported a record number of cases.

Johnson is hoping to curb the impact of infections by ramping up the country's booster programme, having pledged to try to offer a third dose to all adults by the end of the month.

Officials said more than 510,000 were jabbed Monday -- nearly double the number a week earlier but far short of the ambitious one million-a-day target.

Although expanding boosters enjoys cross-party support in Westminster, Johnson's latest restrictions have proved more contentious.

Hardline Tory MPs accused his ministers of enforcing "disproportionate" curbs based on incomplete evidence that will invariably lead to further measures.

One MP went so far as to compare the introduction of vaccine passes in certain settings to Nazi Germany, triggering protests from Jewish groups.

After the vote, Geoffrey Clifton-Brown, treasurer of the 1922 Committee of backbench Conservative MPs, told Sky News that a leadership challenge has "got to be on the cards" next year.

The display of defiance contrasted starkly with previous parliamentary votes, which effectively rubber-stamped Covid rules, and could not come at a worse time for Johnson.

The 57-year-old has seen support plummet in opinion polls, and faced open calls to quit because of reports that he and staff broke coronavirus rules at Downing Street last Christmas.

That added to claims of cronyism and corruption after reports that the government handed wealthy Tory donors plum seats in the unelected upper chamber, the House of Lords.

Johnson also caused fury by trying to change parliament's disciplinary rules after a Tory MP was found to have lobbied ministers for two companies that had him on their payrolls.

The MP, Owen Paterson, later quit, forcing a by-election in his North Shropshire constituency on Thursday -- the result of which could make Johnson's position even more fragile.

Paterson had a 23,000 majority at the last election in 2019 but a significant cut in that or even a defeat in the Tory safe seat could spell doom for the embattled prime minister.