MP Heidi Allen, who quit the Conservative Party earlier this year, has joined the Liberal Democrats.
The MP for South Cambridgeshire left the Conservatives in February over its Brexit policy and other issues.
She subsequently became the leader of the fledgling Change UK but left after the party's failure to win any seats in the European elections.
She is the fourth ex-Tory to join the Lib Dems in recent months, after Sarah Wollaston, Philip Lee and Sam Gyimah.
Her move means the Liberal Democrats now have 19 MPs, eight more than at the start of the year.
https://www.bbc.co.uk/news/uk-politics-49967901