EU warnings ahead of treaty signing

The cross-party European Scrutiny Committee warned that the sovereignty of the British Parliament was being put at risk by the document's "ambiguous" wording.

Its Labour chairman, Michael Connarty, predicted a steady transfer of control over criminal justice matters to the European Commission and the European Court of Justice.

The committee has previously described the treaty as being largely similar to the EU Constitution dumped by French and Dutch voters in 2005.

In a new report, it stepped up criticism that the development of the treaty to overhaul the EU's structures had been shrouded in secrecy and excluded the public. "The process could not have been better designed to marginalise the role of national parliaments and to curtail public debate, until it has become too late for such debate to have any effect on the agreements which have been reached," the committee said.

It went on to say that MPs had not been convinced by Foreign Secretary David Miliband's assurances that the final draft would contain no obligations on Westminster to the EU. And it expressed alarm that ministers had failed to secure an opt-out from the new Charter of Fundamental Rights, saying that a UK Protocol would not excuse Britain from the need to comply with rulings by the European Court of Justice.

Mr Connarty added that Britain's "opt-ins" on justice and home affairs matters would also surrender jurisdiction from the UK courts, while choosing not to opt-in would present "new and unquantifiable risks".

The report comes two weeks before the Prime Minister is due to sign the treaty, after which it faces lengthy and heated debate in Parliament before ratification.

Mr Brown is resisting intense pressure from the Conservatives for a referendum on the treaty to fulfil Labour's manifesto commitment to giving the public a say on the Constitution.

Ministers insist that there is no need for a referendum as the treaty is substantially different from the Constitution.