The Deputy Prime Minister has put distance between the Liberal Democrats and the Conservatives.

Nick Clegg denigrated the Tories' stance on Europe and their desire for a tax break for married couples at his first monthly press conference.

With just days to go before Tory MPs line up to demand an immediate in-out referendum on Britain's membership of the European Union, Mr Clegg – whose pro-Europeanism is part of his DNA – let rip at the Conservatives.

Responding to calls from David Cameron to "get off the fence" and turn up to vote on Friday, the LibDem leader told reporters his party would not "waste any of our time helping the Conservatives indulge in their own internal feuds" as he insisted his party had been consistent on the referendum issue while Mr Cameron had "swerved around enormously".

Mr Clegg dismissed the Prime Minister's "ill-defined process of so-called renegotiation", accusing him of plucking the 2017 referendum date out of thin air.

Insisting the Tories were increasingly in thrall to "loopy" ideas from their right wing, Mr Clegg also attacked his Coalition partners on marriage tax breaks.

He said: "This desire of the Conservative Party to hand-pick couples through the tax system who confirm to their image of the way you should conduct your life.

"I don't think it's fair on all those other people who would pay higher taxes to fund this proposal."

The Lib Dem leader said if there were millions of pounds going spare, he would rather spend them on helping working families with child care costs.

Mr Clegg also attacked Nigel Farage's Ukip for wanting to return to a sepia world of the 1950s.