At last....Downing Street finally admits EU treaty is just a rehash of scrapped constitution

Gordon Brown has so far rejected demands for a vote on the treaty, claiming it was different to its predecessor.

But in an extraordinary U-turn, No10 conceded for the first time that the two documents are virtually identical.

The Prime Minister's spokesman explained the admission by saying that for countries who had not secured special deals the treaty was 'substantially equivalent' to the constitution.

He insisted Britain was different because ministers had negotiated to protect key 'red lines' on crime and justice, human and social rights, foreign policy and taxes.

Mr Brown has repeatedly claimed the 'constitutional concept' had been abandoned and has resisted calls for a vote claiming the treaty was 'substantially different' to the constitution.

But MPs and campaigners said No 10's confession proved the public should be given a vote as promised in Labour's manifesto.

Downing Street's comments came in the wake of a report by the Commons European Scrutiny Committee which said the treaty was 'substantially equivalent' to the constitution, thrown out by French and Dutch voters in 2005.

In a line-by-line study, it found only two of 440 provisions were different - on symbols, including a flag, and an anthem.

It also warned the red lines were worthless because the Government had no legal protection in the treaty preventing it being forced to surrender key powers to Brussels 'bit by bit'.

Asked whether the treaty 'substantially had the aspects of a constitution' for countries which did not have Britain's opt-outs, No10's spokesman replied: "It does."

But he added: "The treaty that applies to other countries does not apply to the UK."

Foreign Secretary David Miliband and Europe Minister Jim Murphy were sticking by that line last night.

But committee chairman Michael Connarty said the treaty would give the European Court of Justice more power to ignore Britain's opt-outs.

He went on: "The red lines will not be sustainable. We believe these will be challenged bit by bit and eventually the UK will be in a position where all of the treaty will eventually apply.

"If they can't get these things firmed up, we think they will leak like a sieve.

"The Government has got to redraft it in a way that we in the UK are happy that these red lines will not be broken down over the longer term."

Neil O'Brien, of the Eurosceptic think-tank Open Europe, said the warning was a 'big turning point', adding: "The Government's case against the referendum is unravelling. The red lines will not protect Britain."

Shadow foreign secretary William Hague said Mr Brown's failure to hold a general election meant he had 'no mandate' to sign the treaty.

Mr Murphy insisted the opt-outs were 'watertight legally' and dismissed the finding that the treaty and the Constitution were largely the same.

On Monday, Mr Brown promised to hold a referendum if Britain's safeguards failed, saying: "If our red lines are not achieved, we will either veto it or say there has to be a referendum."