A European constitutional treaty would have profound implications for the UK and "raise issues of principal" for Britain's constitution, a Lords report concluded yesterday.
The report identified 15 areas where the draft EU treaty would pose "constitutional concerns for the UK", including the future sovereignty of Parliament.
The select committee report said there would be an impact on Britain's criminal justice system because the treaty would increase the EU's powers "in the criminal law field", with a European public prosecutor. Foreign policy could also be affected by the creation of an EU foreign minister.
The findings of the House of Lords Select Committee on the Constitution will be seized on by Eurosceptics and those calling for a referendum on the treaty. Yesterday Jack Straw, the Foreign Secretary, faced renewed calls in the House of Commons for a referendum from both the Tories and Liberal Democrats. But Mr Straw, who attended last week's EU summit with the Prime Minister where the draft EU constitution was discussed, defended his decision not to put the issue to the public.
Menzies Campbell, the Lib Dem foreign affairs spokesman, said: "This report simply confirms the view which the Liberal Democrats have formed that, in spite of what the Government says, there are constitutional issues at stake in the proposed treaty. The case for a referendum is overwhelming."
The report includes submissions from experts on the effects of the draft treaty which will reorganise the provisions governing the EU.
The peers concluded that it will "change the structure of the EU" and the way it works, including its relations with member states.
It highlights constitutional concerns such as the ability of British bodies to influence the EU after the introduction of further qualified majority votes. It also raises the future status of the Charter of Fundamental Rights and "whether continuing development in the European Union will have material effects upon the constitutional doctrine of the sovereignty of Parliament".
The peers warn that the treaty could have implications for government in Scotland, Wales and Northern Ireland. They said they wanted to study these issues in greater detail and draw them to the attention of those negotiating the treaty.
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