Irish voters are expected to reject the Lisbon Treaty in a poll on Thursday, putting pressure on MPs and peers to halt the ratification process in the UK.
A poll in the The Irish Times showed "no" campaigners had the backing of 35 per cent of voters, twice the level of support from a week ago. The "yes" campaign has the support of just 30 per cent, down five points.
Gordon Brown's hopes of avoiding defeat in Parliament on the European Union treaty were fading last night after the Irish poll showed a growing negative trend.
There was speculation in Westminster that the Prime Minister could be persuaded to use a "no" vote in the Republic to drop the EU treaty Bill that is currently before Parliament – allowing him to appear as if he is listening to voters while avoiding additional political pressure.
The Bill to ratify the treaty in Britain was approved in a vote of MPs in March, but it faces a more difficult passage through the House of Lords.
Peers will next vote on the treaty on Wednesday and a final vote – giving the go-ahead for ratification by the UK – will take place on 18 June, the day before an EU summit where leaders will attempt to push ahead with the treaty's key changes.
Talks are due to begin about the creation of posts for a permanent EU president and a foreign minister.
There are fears that the "no" vote will destroy any chance of progress in Europe, after the EU constitution was rejected by both French and Dutch voters in 2005.
All 27 member countries in the EU must ratify the treaty. But in the event of a "no" vote in Ireland, officials in Brussels could try to hold an emergency summit of EU leaders before demanding a repeat referendum.Reuse content