Chuka Umunna with Sir Vince Cable yesterday. Mr Umunna said that the electoral system was “unforgiving” to start-up parties

Chuka Umunna is to join the Liberal Democrats, saying that he was wrong to believe that there was a need for a new political party in the centre ground of British politics.

The MP for Streatham, who briefly stood for the Labour leadership in 2015 and quit to sit as part of an independent group in the Commons in February, will become the Lib Dems’ 12th MP.

Sir Vince Cable, the party’s outgoing leader, hailed him as a “formidable, serious political figure” who would be a positive addition. Mr Umunna, who once said that he could never forgive the Lib Dems for “enabling Tory austerity”, was braced for the brickbats, however.

“I’ve got a pretty thick skin,” he said when asked