Tory backbenchers have heavily criticised the Prime Minister's objectives for the renegotiation of the UK's membership of the EU.

David Cameron has set out four main points for the renegotiation: the UK being made exempt from the EU commitment of ever closer union, restricting benefit payments for migrants, protection for the UK from eurozone integration and a drive for improved competitiveness.

But a number of vocal backbench Conservative MPs do not believe the PM's demands go anywhere near far enough.

Jacob Rees-Mogg, Tory MP for North East Somerset, was damning in his criticism as he addressed the House of Commons following a statement made by Europe Minister David Lidington.

"You must know that this is pretty thin gruel - much less than people had come to expect from the Government," he said.

"It takes out a few words from the preamble but does nothing about the substance of the treaties.

"It deals with competition for which the European Commission itself has a proposal.

"It fails to restore control of our borders.

"It seems to me that its whole aim is to make Harold Wilson's renegotiation look respectable.

"It needs to do more. It needs to have a full list of powers that will be restored to the United Kingdom and to this parliament, not vacuously to parliaments plural."

Sir William Cash, Tory MP for Stone, described the negotiation plan as a "pig in a poke".

He asked the Minister: "Does he not accept that treaty change is needed for virtually every proposal?

"Furthermore that treaty change is not on offer, so how are the so called legally irreversible changes going to be made when even the legal expert from the European Commission says that the Danish and Irish precedents are not valid.

"How is he going to be able to sell this pig in a poke?"

Mr Lidington told the House that "some, but not every aspect of the package of reforms that we are seeking will need treaty change".

Meanwhile, Peter Lilley, Tory MP for Hitchin and Harpenden, called on the Government to deliver more than just "symbolic" changes.

He said: "Will you avoid using up your limited bargaining power to obtain purely symbolic changes like removing the words 'ever-closer union' given that they have never been invoked by the European Court against Britain or to require any other member state to move in an integrationist direction and were even dropped from the constitutional treaty.

"Will he instead focus on getting back powers which are not required to run a common trading area so that this parliament can make more of our own laws and hold our lawmakers to account?"

Mr Lidington said what the PM is seeking is a "deal on reform which is substantive and which it will be challenging to negotiate".