Former Conservative leadership contender Sam Gyimah has defected to the Liberal Democrats on the first day of the party’s conference in Bournemouth.
The ex-universities minister was revealed as the Lib Dems’ 18th MP at a Saturday evening rally, telling party members he had joined to “help create a new force in British politics”.
Mr Gyimah becomes the third former Conservative MP to have joined the party in the last month, with three ex-Labour MPs also having joined the Lib Dems this year.
The East Surrey MP had put himself forward as a candidate for the Conservative Party leadership as recently as June.
He advocated a second EU referendum but withdrew from the race eight days later and before the first ballot of Tory MPs.
Mr Gyimah was this month effectively expelled from the Conservatives along with 20 of his colleagues, having the party whip removed after voting against the government on Brexit.
The rebel group had supported legislation that will compel Prime Minister Boris Johnson to seek a fresh three-month delay to Brexit if he fails to negotiate a new withdrawal agreement with the EU by 19 October.
Conservative whips recently offered a route back into the party fold for the 21 rebels by writing to each of them to set out an appeals process.
But Mr Gyimah revealed, on a podcast he co-hosts with fellow former Tory minister and now Lib Dem MP Phillip Lee, that he would be rejecting the offer.
He said on the podcast, published on Friday: “I have said, given the letter I received, that I am not going to be accepting the whip back because the policy hasn’t changed.
“So I will be reflecting very deeply on what I do next this weekend.”
At their conference in Bournemouth, Lib Dem members will vote on whether to support the outright cancellation of Brexit as a new policy.
The party has previously supported stopping the UK’s departure from the EU via a second referendum.
But, in a motion to be voted on by party members on Sunday, the Lib Dems will propose campaigning at the next general election on a “stop Brexit” platform.
Lib Dem leader Jo Swinson told the House of Commons this week: “In a general election, where we will stand to secure a Liberal Democrat majority, such a Liberal Democrat majority government would indeed revoke Article 50.”
Which MPs have already defected to the Lib Dems?
Chuka Umunna, former Labour MP who quit the party to help found new party Change UK. He is now the Lib Dems’ foreign affairs spokesman.
Sarah Wollaston, ex-Tory MP who is also a former member of Change UK. She is chair of the House of Commons’ influential liaison committee.
Luciana Berger, quit Labour in anger at what she described as the party’s “institutional antisemitism”. She also helped found Change UK before joining the Lib Dems.
Phillip Lee, ex-Tory justice minister who dramatically crossed the floor in the House of Commons to sit with the Lib Dems.
Angela Smith, former Labour MP and another founding member of Change UK. She is an ex-Labour whip.