Deputy Prime Minister Nick Clegg hit out at critics of the new coalition's plans to make it more difficult for MPs to force out the Government if it is defeated on a vote of confidence.
In his first setpiece speech since taking office last week, the Liberal Democrat leader said the proposed new requirement for a 55% majority of MPs to agree to a dissolution of Parliament before the end of its five-year term would help ensure stability.
He accused critics who have claimed that it would make it more difficult to get rid of a government that had lost the confidence of the House of Commons of "completely missing the point".
Although he aimed his remarks at Labour former ministers such as Jack Straw and David Blunkett who have attacked the plan, it risks antagonising Conservative MPs who have also voiced opposition to the proposal.
In a wide-ranging address to students in north London, Mr Clegg also promised a review of the anti-terrorism laws to prevent their "misuse" by the authorities.
Mr Clegg acknowledged that the plans for five-year fixed-term parliaments would need to be worked out, but said that the Lib-Con coalition Government believed that a 55% majority vote for an early dissolution was the right course.
"That is a much lower threshold than the two-thirds required in Scottish Parliament but it strikes the right balance for our Parliament, maintaining stability, stopping parties from forcing a dissolution to serve their own interest," he said.
"This last week, former Labour ministers who were once perfectly happy to ride roughshod over the rights of Parliament are now declaring that this is somehow an innovation which is a constitutional outrage. They are completely missing the point.
"This is a new right for Parliament, additional to the existing powers of no confidence. We are not taking away Parliament's right to throw out government. We are taking away government's right to throw out Parliament."
On the anti-terrorism laws, he said that new safeguards were needed to prevent their misuse. He said: "There have been too many cases of individuals denied their rights and whole communities being placed under suspicion. This Government will do better by British justice, respecting great British freedoms."