George Osborne has labelled the defection of Douglas Carswell to Ukip as "regrettable and counter-productive".
Speaking in Brighton today, the Chancellor said that the best way to secure a referendum on Britain's membership of the European Union was to have a Conservative government after the next election.
"That's the choice people are going to face, whether it's at the by-election in Clacton or at the general election next year," Mr Osborne said.
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