British lawmakers debated unpopular plans on Tuesday to extend the number of days British police can hold terrorism suspects in custody before they are charged.

Prime Minister Gordon Brown hopes to give police up to 42 days to detain suspects before charges are filed, extending the current limit of 28 days.

Brown said the extension could be needed to cope with simultaneous terror attacks, when complex investigations are likely to slow the ability of police to gather evidence.

But many lawmakers, civil liberties campaigners and some key counter-terrorism officials insist that no change is needed to current laws.

“In our experience, the 28-day limit works well,” Britain’s chief prosecutor, Ken Macdonald, told The Times of London on Tuesday, saying he does not back Brown’s proposals for tougher terror laws.

Tony Blair, Brown’s predecessor, suffered a humiliating first parliamentary defeat in 2005, when lawmakers voted against his plan to extend the maximum detention to 90 days.

Legislators instead settled on the 28-day limit.

Brown said on Tuesday the new laws would include a raft of safeguards and insisted the 42-day limit would only be used after Parliament had voted to authorise it in each case.

“The most important thing is that Parliament has got to vote,” Brown told reporters at his owning Street office.

“There will come a time when there are multiple plots or particular difficulties emerge where we will have to ask for a greater detention power than 28 days.”