A fresh wave of defeats in the House of Lords has left the government's anti-terrorism plans in disarray.

In a succession of votes on Tuesday evening, peers voted for a new set of amendments to the Prevention of Terrorism Bill.

A majority of 187 backed a Conservative push to ensure that the legislation expires in eight months' time.

Two other amendments, also backed by majorities of over 100, insisted that the Bill must list the range of possible control order measures and moved to protect suspects' rights to state benefits.

Home Office minister Hazel Blears said she would "look very carefully at what the lords have done".

She insisted the government was "trying to strike the right balance" between national security and civil liberties.

Speaking to Sky News, Blears said there had been "significant movement" on the legislation from the government.

The minister also said the government wanted to "get some legislation that protects national security".

If the legislation is to make the statute book, the government will have to accept some or all of the amendments when MPs debate the plans later this week.

Shadow home secretary David Davis said the outcome "speaks volumes about the cross-party support" for the sunset clause and warned the prime minister he "cannot and should not ignore this".

"The prime minister should face reality and appreciate there are serious concerns across the parties about this Bill which threatens our civil liberties, and that a sunset clause will deal with these without leaving our country exposed to terrorists," added Davis.

More defeats

On Monday night peers voted by a majority of 130 to amend the bill so that all control orders can only be imposed on a terror suspect by a judge.

Charles Clarke had proposed that he, rather than the courts, should be responsible for control orders that fall short of imposing house arrest.

Under the amendment, the home secretary would have to apply to a high court judge who would then decide whether to impose the order.

In a further amendment, peers raised the burden of proof to the "balance of probabilities" before an order could be imposed.

In a third amendment the director of public prosecutions would also have to agree, having examined the suspect's file, that a normal prosecution could not take place.

Unchanged position

Downing Street said on Tuesday that Tony Blair continued to believe in the importance of passing the legislation.

"The prime minister's position remains unchanged from yesterday," Number 10 said.

"His view which is shared by ACPO [Association of Chief Police Officers] and many others is that we need a range of powers to deal with this group of extremely dangerous individuals.

"We have to be very careful we do not send the wrong signal to the terrorists about our intent and the wrong signal to the police and security services about the seriousness of our resolve."

When asked whether any concessions would be forthcoming the official spokesman would only respond "the Commons will deal with the Bill as it returns from the Lords".