British Prime Minister Boris Johnson on Friday suffered a crushing by-election defeat in a constituency never previously lost by his Conservative Party, a result which raises serious questions about his leadership.

His party won the seat in North Shropshire, central England, by a massive majority in 2019, but the Liberal Democrats won Thursday's poll by nearly 6,000 votes in a result that will intensify the mutinous mood among Conservative MPs.

Johnson, 57, was already reeling after roughly 100 of his own MPs rebelled in parliament Tuesday against the government's introduction of vaccine passes for large events.

The UK leader's authority has also been clobbered repeatedly in recent weeks by claims of corruption and reports that he and his staff broke coronavirus restrictions last Christmas.

Weeks of bad headlines have turned what would normally be a routine victory in the safe rural seat into a far more fraught process for Johnson's Tories, while surging virus cases have added to a sense of crisis.

The government reported nearly 89,000 new infections Thursday, the second consecutive record daily tally.

Ahead of polls opening in the seat of about 80,000 voters, Johnson appeared to be struggling to convince locals to stick with him, prompting predictions of a historic loss in a seat where the previous Conservative MP won a 23,000 majority in the last election.

Gloomy outlook 

The atmosphere is a far cry from May, when the Conservatives swept to an unprecedented by-election victory in the northeast England seat of Hartlepool on the back of a successful vaccine rollout.

But the virus is dominating British life again and the arrival of the Omicron variant has again deepened the gloom before Christmas, with the prime minister's authority seen as weakened. 

Britain is also suffering spiralling inflation as a result of big borrowing during lockdowns, high energy prices and bottlenecked supply chains. Tax rises also loom from next April.