Britain's Prime Minister Theresa May leaves Downing Street in London, September 11, 2018. REUTERS/Toby Melville

LONDON (Reuters) - Lawmakers from British Prime Minister Theresa May’s Conservative Party can vote against her Brexit plans without it being a vote of confidence in her government, the head of an influential group of pro-Brexit lawmakers said on Tuesday.

Brexiteers have said as many as 80 of May’s 315 lawmakers could vote against her so-called Chequers plan, leaving the fate of the government and the Brexit deal in the hands of the opposition Labour Party.

If she loses that vote, Britain could leave the EU without a deal, an outcome some believe would spark a crisis of confidence that could cost her the premiership.

Jacob Rees-Mogg, chair of the European Research Group, a faction within May’s Conservatives, plans to vote against the Chequers deal but said that does not mean May has to go.

“The vote on the legislation will not be a vote of confidence,” Rees-Mogg, tipped by some as a possible successor to May, told a pro-Brexit event in parliament.

“We can vote down the bad Chequers proposals on Monday and support the government in a vote of confidence on Tuesday. They are separate things and trying to align them I think is a mistake. So we can carry on supporting the prime minister but we can oppose this policy until it is changed or collapses.”