By political editor Paul Francis

David Cameron’s decision to abandon plans for a referendum on the Lisbon Treaty has led the outspoken Kent-based European MEP Daniel Hannan to quit his frontbench job.

The MEP, well-known as a Euro-sceptic, quit his role as the party’s legal affairs spokesman in the European Parliament saying he wanted to concentrate on campaigning for a referendum on Europe.

Writing in his Daily Telegraph blog, the MEP said he was returning to the backbenches to build a movement that would "push for referendums, citizens' initiatives and the rest of the paraphernalia of direct democracy".

He said that virtually all the country’s MPs had been elected on the back of various promises that there would be a referendum.

“The legitimacy of our representative institutions is at stake. Out of 646 MPs in Westminster, 638 were elected on the a promise of a referendum. True, the Lisbon Treaty is now in force. But there is nothing to prevent us having a referendum on whether we, as a country, participate in its provisions,” he said.

Meanwhile, out-going UKIP leader and Kent MEP Nigel Farage sought to exploit the Conservative party’s discomfort over its referendum U-turn.

"First we had the Labour Party withdrawing their promise of a referendum, then the Lib Dems and now we have the Tories showing they are not to be trusted either. UKIP is the only party to be trusted on this issue and will continue to fight for this crucial referendum that all the other parties promised but will never deliver."