The former Conservative MP Sarah Wollaston has joined the Liberal Democrats in a much-anticipated move, the party has announced.

On the more pro-remain and socially liberal side of the Tories, Wollaston quit the party in February with colleagues Anna Soubry and Heidi Allen to join the group that became Change UK.

In June, she was among six of Change UK’s eventual 11 MPs who left to become independents, amid splits over tactics in the group. One of these was the former Labour MP, Chuka Umunna, who then moved to the Lib Dems.

The MP for Totnes since 2010, after she was chosen by a then-innovative open selection process, Wollaston is a former GP who chairs the Commons health and social care committee.

With the Lib Dems’ victory at the start of the month in the Brecon and Radnorshire byelection, Wollaston is the party’s third new MP in recent months in a move that boosts their number to 14 in the Commons.

Wollaston said in a statement she was “delighted to be joining the Liberal Democrats under the leadership of Jo Swinson”.

She said: “I believe the best way for me to represent my constituents in Totnes is to be working as part of a fantastic team of Liberal Democrat MPs who are unequivocally making the case for us to remain at the heart of Europe, as well as campaigning for social justice, the environment and our public services.”

Swinson said: “I am delighted to welcome Sarah to the Liberal Democrats. We have worked together for many months to fight to stop Brexit and, as one of the most respected members of parliament, she brings real expertise to our team.

“The Liberal Democrats are growing – over 30,000 people, alongside Sarah, have joined us since our best ever results in the European elections in May. As the strongest party for remainers, we will lead the fight to stop Brexit.”

Wollaston was expected to join Swinson at a speech the Lib Dem leader is due to give in London on Thursday morning.

