BBC: The EU treaty is "substantially equivalent" to the EU Constitution thrown out by Dutch and French voters in 2005, MPs have said.
The European scrutiny committee said it should be "made clear" the UK can keep opt-outs of parts of the document.
The Conservatives said the government was now "morally bound" to hold a referendum on the treaty, as had been promised on the Constitution.
But ministers say the two documents are "substantially" different.
The treaty incorporates some of the old EU Constitution, on which Labour had promised a referendum before it was scuppered by the Dutch and French votes.
The Conservatives argue it is as much as 90% the same. EU treaty 'same as Constitution' (more)
Mark Alexander
