Labour voters ready to rebel in row over a Euro referendum

A poll for the Daily Mail also reveals that more than eight out of ten of the wider public want a national vote on the revived Brussels treaty.

More than half say the EU already has too much power over our lives.

But the most alarming finding for the Prime Minister, is 24 per cent of Labour supporters would be less likely to vote for him at the next General Election if they are denied a referendum.

Some 13 per cent of Labour voters would even consider switching to the Tories if David Cameron promised a referendum, the ICM poll reveals.

The row over the new EU treaty is emerging as one of the key flashpoints in a possible snap election this autumn. A rebellion by one in four of the 9.5million who voted Labour in 2005 could cost Mr Brown victory.

A backlash against the Government on the new constitution has grown

since June, when Tony Blair struck a deal with European leaders as one of his final acts as PM.

In Labour's 2005 election manifesto, Mr Blair promised a referendum on the original EU constitution. But it was rejected by French and Dutch voters later that year, removing the need for a UK vote.

The Government is now refusing to put the new treaty to the British people, claiming it does not involve the same transfer of powers to Brussels as the old draft. EU experts, however, say the two documents are nearly identical, so the British people should have their say.

The Daily Mail's poll reveals that 82 per cent of all voters and 80 per cent of Labour supporters want a referendum.

The figures reflect growing concern within the Labour party.

Scroll down for more

Click enlarge to see the full text

Up to 40 Labour MPs are said to be considering mounting a backbench campaign for a referendum. They include Gisela Stuart, one of the EU group which drafted the original constitution.

Labour-supporting trade unions are adding to the pressure on Mr Brown. The GMB has called for a referendum and the Transport and General Workers

Union has come out against the treaty.

The row could be a major issue at the TUC conference next month.

Opponents claim the treaty will mean a major handover of British rights and powers to Brussels, including in areas such as transport, energy and immigration.

Research by the Tories and the Open Europe think-tank shows that, apart from the removal of presentational measures like an EU flag and anthem, the new treaty is fundamentally the same as the old one.

Surviving measures include the creation of an EU president, an EU foreign minister with a diplomatic service and a "single legal personality" which would allow the EU to sign treaties. There would be beefed-up powers for the European Commission, Court of Justice and European Parliament.

The Irish government has said that 90 per cent of the old constitution is in the new treaty, while the Spanish government claims it is 98 per cent similar.

The Foreign Office insists that the UK has key 'red lines' where it could opt out of majority decisions.

But the Tories say these are exactly the same as in the rejected 2005 constitution - which merited a referendum.

Tory spokesman Mark Francois said last night: "This important poll reveals that even traditional Labour supporters are now becoming angry at Gordon Brown's refusal to grant a referendum.

"This revelation will further increase pressure on Brown to honour the Labour manifesto commitment and give our people the vote they were promised all along."