UK referendum bid defeated

The Lisbon treaty was signed by EU leaders in December 2007 and it must be ratified by all the bloc's member states before taking into force. Most countries have opted for a parliamentary ratification, with only Ireland due to hold a referendum on the issue, probably in June.

The push for a popular vote in Britain was due to a manifesto pledge before the 2005 general elections by all three main political parties to ask citizens for their approval of the EU constitution.

The constitution was subsequently rejected by French and Dutch voters in mid-2005, but the current treaty contains most of its innovations.

While the UK's ruling Labour party as well as the Liberal Democrats claim the Lisbon treaty no longer has constitutional implications for Britain and so does require a referendum, the Conservatives insist the document is the constitution but with a different name.

"We have the courage of our convictions and are sticking to that promise - you have lost your courage," Conservative leader David Cameron told the prime minister in a passionate debate in parliament.

Mr Brown hit back by saying: "If this was a constitutional treaty, we would hold a referendum. But the constitutional concept was abandoned."

The Labour MPs also referred to several "opt-outs" from the Lisbon treaty that the government had negotiated, mainly on citizens rights, and justice and home affairs.

But Wednesday's vote showed some differences of opinion within the political parties over their own official lines on the treaty. Some 29 Labour MPs and 13 Liberal Democrats voted with the Conservatives in favour of a referendum, while three Conservatives voted against their party line.

Britain is now expected to ratify the treaty by the summer. So far, five countries have given the green light to the document: Hungary, Slovenia, Malta, France, and Romania.