UKIP economic spokesman Patrick O’Flynn has accused David Cameron and Nick Clegg of preparing for a “rigged referendum” on EU membership.

Mr O’Flynn, who is also UKIP’s campaign director, spoke out after a report in the Financial Times said that Mr Clegg’s support for a referendum would depend on him helping to determine the question posed, the timing of the event and who would be allowed to vote.

The Lib Dems are reportedly demanding that millions of EU migrants should participate, as well as pushing to include 16 and 17-year-olds who are statistically more likely to hold pro-EU views.

Mr O’Flynn said: “We already know that David Cameron is quietly preparing the ground for another coalition with Mr Clegg. Now we are learning how they plan to get over the hurdle of an EU referendum that the Lib Dems are not overly keen on – they are preparing to rig it.

“It would be profoundly unfair were millions of EU migrants allowed to vote in Britain’s referendum, while extending the franchise to 16 and 17-year-olds is clearly intended to tilt the result as school-leavers are much more likely to have been recently exposed to heavily pro-EU views.

“This plan to rig the referendum makes it ever more clear to the British people that only by electing a good number of UKIP MPs into the House of Commons can they be confident of getting what they deserve: a free and fair choice about how they are governed.”