Amid claims of a Commons "farce", a rebellion over new anti-terrorism powers last night saw the government's majority slashed to just 14.

Charles Clarke had already announced one major concession, saying that judges rather than himself would issue orders for house arrest.

But the home secretary insisted that he should retain the power to issue restrictions short of house arrest, such as banning access to mobile telephones.

The plans failed to win over many of the government's critics, and in a vote on ensuring a judge decided on all control orders, some 253 MPs backed the proposal with 267 against.

Some 60 Labour MPs, including four former Cabinet ministers, joined the revolt.

After narrowly surviving the Commons, the focus now moves on to the Lords, where peers will debate the amendments to be put forward by Clarke.

The failure to unveil the amendments during the debate in the lower house prompted further anger among MPs.

At the start of the debate it emerged that Clarke had written to his Conservative shadow David Davis outlining his new position.

But MPs were left with no amendments to debate, and unsure whether to vote for the government's original plans or their own amendments that could become irrelevant.

Former Conservative home secretary Kenneth Clarke said he had never heard of such a procedure being followed before, saying: "It is a complete outrage... it reduces our proceedings to a farce."

There was further confusion when Tony Blair suggested that "several hundred people" are plotting terrorist attacks in Britain.

The prime minister's warning was not backed by Clarke, who insisted the control orders would affect only "a small number of people".