DAVID Cameron has been accused by Labour of "signalling retreat" on his ambitious plans to renegotiate the UK's relationship with the European Union.

It came after the Prime Minister was forced to accept that there might be no change to the bloc's treaties before Britons voted in the promised referendum.

Yet as Mr Cameron tucked into his dinner at the European Council, over which he discussed his plans for reform, UK officials were keen to stress that he would secure "legally binding and irreversible" assurances from his 27 counterparts that EU law would indeed be changed to incorporate his desired reforms on matters like welfare.

These assurances, they insisted, would be "crystal clear" to voters before they went to the polling booths.

One No 10 source made clear Mr Cameron remained committed to "proper, full-on treaty change".

But John Redwood, the Eurosceptic Tory MP, claimed the EU could not be trusted.

"We should never trust what the EU says. They change their mind more often than I change my shirts, which is very often," the former Welsh Secretary said of the guarantees Mr Cameron was seeking.

Treaty change requires the ratification of every member state and in some cases like France, Ireland and Denmark a referendum.

Nigel Farage insisted the PM was "accepting the inevitable", that is, there would not be EU treaty change before the UK electorate voted because the "big figures" in the EU had said No.

The Ukip leader claimed it was now clear there would "not be a fundamental change of the UK's relationship with the European Union".

But the Europhile Damian Green, the ex-Conservative Home Office Minister Damian Green, argued that it was "perfectly sensible for the Prime Minister to leave his options open" to get the results he wanted.

"It's obvious that a treaty change would require referendums in other countries so it would be a very long, drawn-out process. You can see why other countries won't welcome that," he added.

Yet Hilary Benn for Labour was scathing about Mr Cameron's apparent retreat. "All year the Prime Minister has been saying that change to the treaty was a definite requirement and yet now, faced with entirely predictable opposition from other member states, he is signalling retreat while pretending that all he ever wanted was a post-dated cheque."

The Shadow Foreign Secretary accused the PM of having "made a mess" of his negotiation process.

"He should have known what the position of other countries would be but, because he did not prepare the ground, for the second time in a few months he has been forced to admit that he can't get what he wants."

Mr Benn claimed the same pattern kept repeating itself. "He marches his troops up to the top of the hill and then he has to march them down again. He is so intent on keeping his Eurosceptic backbenchers at bay, that a calm negotiation of what is in the country's interests - remaining a member of the European Union - comes second."

Meantime, attempts to break the deadlock in the Greek debt crisis will carry on into the weekend after the latest talks to avert a catastrophic default by the radical left Syriza government broke up without agreement.

Tomorrow, finance ministers from the 19 eurozone countries are set to return to the negotiating table in the Belgian capital after their third meeting in four days failed to produce a breakthrough.

Unless Athens is able to strike a deal with its creditors which allows it to gain access to a fresh tranche of £5.1 billion in bailout funds by Tuesday, it will miss a £1.1bn payment to the International Monetary Fund and be declared in default, which could send it crashing out the single currency.

Despite the high-stakes brinkmanship, and with time for an agreement running out, Greek Prime Minister Alexis Tsipras insisted a settlement was still possible.

"European history is full of disagreements, negotiations and, at the end, compromises. So, after the comprehensive Greek proposals, I am confident that we will reach a compromise," he said.