A former Labour MP and close ally of Jeremy Corbyn has defected to the Liberal Democrats after calling his former party a “political basket case”.

Bob Marshall-Andrews, the barrister who represented Medway from 1997 to 2010, denounced the “abject failure of the Labour leadership” over the Brexit referendum campaign.

Mr Marshall-Andrews, who sat in the socialist group of Labour MPs alongside Mr Corbyn, said that the Labour Party’s failure to lead the arguments against Brexit had “provided a concession of both votes and credibility to Ukip”.

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He suggested that the party appears lifeless, saying: “At present there is manifestly a huge vacuum on the centre-left represented in substantial part by the 48 per cent of the electorate who rejected Brexit and the lies on which