Boris Johnson has avoided campaigning in North Shropshire for a fortnight ahead of Thursday’s by-election, amid fears the Conservatives could face a deeply embarrassing defeat.

The Prime Minister has not returned to the Conservative safe seat, which the Tories held at the last general election with a 23,000 majority, since December 3.

Tory sources have said that he has been dealing with the outbreak of the omicron variant. However Sir Ed Davey, the Liberal Democrat leader, has spent 10 days on the campaign trail, including five overnight stays.

The party believes the seat, previously held by Owen Paterson before his resignation amid the parliamentary sleaze scandal, is on a “knife-edge” between the Tories and Liberal Democrats.

The Liberal Democrats believe that Mr Johnson’s chaotic Peppa Pig speech and planned changes to subsidy payments for farmers have “cut through on the doorstep”.

“The momentum for the Lib Dems is there and Labour doesn’t have a hope,” said a party source.