London now has four Liberal Democrat MPs after welcoming Chuka Umunna to the party.
Elected in 2010, the Streatham MP brings passionate anti Brexit views and strong liberal values, as well as experience of serving as Shadow Business Secretary. He will be the Lib Dems' Treasury and Business spokesman.
Joining the party, Chuka said: "I have chosen to join the Liberal Democrats because it is at the forefront of a renewed, progressive and internationalist movement in British politics that shares my values.
"I am convinced the Liberal Democrats, as the spearheard of a broader progressive movement in civil society, offer the best chance to improve the lives of those I represent as well as countless other citizens across our country."
Chuka, who left the Labour Party earlier this year to form the independent group which became Change UK, urged others to follow him in joining the Liberal Democrats.
He is the first MP to cross the floor to join our party since 2001.
Chuka's Streatham constituency is in Lambeth, which the Lib Dems won with 32.6% of the vote at the recent European elections, 10 points ahead of Labour.
I am proud to welcome @ChukaUmunna as the Liberal Democrat MP for Streatham.— Helen Thompson #LibDems🔸 (@HelenV_Thompson) June 13, 2019
The @libdems is home for everyone who wants a tolerant, outward-looking, inclusive country. We can't wait to get started working with Chuka to stop Brexit and build a liberal Britain! @LambethLibDems pic.twitter.com/Q5Rhc1pH8S
The Lambeth team's Streatham campaign lead Helen Thompson said: "Chuka has for years been a consistent, compelling and high profile voice against Brexit. He is also a social democrat who agrees with us on core liberal issues, such as tackling inequalities that limit life chances for so many people.
“We welcome Chuka with open arms as our first Liberal Democrat MP for Streatham. I am looking forward to working closely with him to build on our fantastic success in the European elections.”
Chuka joins Lib Dem leader Vince Cable (Twickenham), leadership contender Ed Davey (Kingston) and Brexit spokesman Tom Brake (Sutton) in representing London's Liberal Democrats in Westminster.