|PIC1|Opposition and rebels in the Labour Party will try in parliament on Wednesday to force the government to call a referendum on the new European Union reform treaty.

Many analysts believe the Lisbon treaty, which overhauls the EU's institutions, would be rejected if put to British voters.

Prime Minister Gordon Brown, buffeted by a bank crisis, government blunders and natural disasters during his first eight months in office, opposes a referendum.

Brown sent the treaty to parliament for ratification and debate will continue after Wednesday's vote on a referendum. It would be humiliating for him if parliament were to over-rule him.

But that is highly unlikely to happen, analysts say.

Brown has a working majority of 67 seats and although rebels say at least 20 to 30 Labour MPs may defy the government, Brown's position appears secure because most Liberal Democrats, the second largest opposition party, are likely to abstain.

Robin Shepherd, senior research fellow at the Chatham House thinktank, said the amendment for a referendum had little chance of success.

If Britons rejected the treaty in a referendum, it would be an "enormous blow" for the government, he said. "They will do everything they possibly can to avoid having a referendum."

Britain has a strong strain of Euroscepticism. The country stayed out of the euro and of the Schengen passport-free travel zone and negotiated a series of opt-outs from the Lisbon treaty.

EU leaders adopted the new treaty after French and Dutch voters rejected a proposed constitution in 2005. Brown says the new treaty has been so watered-down it does not need to be put to a popular vote.

The Conservatives accuse Brown - whose party trails in opinion polls - of breaking his word by refusing to call a referendum.

Both the Conservatives and Labour rebels have put forward amendments demanding a referendum. The vote is expected after 7 p.m.

The Conservatives say if they lose the vote on a referendum in the lower house of parliament, they will take the battle to the upper house, where Labour does not have a majority.