Britain's main opposition Labour Party will put forward a motion for a no confidence vote in Prime Minister Boris Johnson's government on Tuesday, with the vote expected to take place on Wednesday, a source in the party said.

The no confidence motion means lawmakers from all the parties represented in parliament can vote on whether the government, under Johnson for the time being, should continue in office. If the government loses the vote, it could trigger a national election.

Although Boris Johnson announced his resignation last week he is currently expected to stay in office until September 5.

Government lawmakers would normally be expected to rally to support the incumbent administration and defeat a no confidence vote, but Labour will be hoping to capitalise on the anger at Johnson among both Conservative MPs and the public to force an early election.

The move comes as the Conservative Party published rules for its leadrship contest to replace Johnson, requiring each contender to have at least 20 nominations from fellow Tory MPs to be able to stand.

Cover photo: Leader of the UK Labour Party and opposition Keir Starmer. Reuters/Henry Nicholls