A SENIOR al Qaida agent was among 12 men arrested in anti-terror raids across England this week, it was reported last night.

The man was arrested on Tuesday as a result of intelligence gathered after a recent raid in Pakistan, according to news reports.

The reports said the al Qaida figure - who went by the codename Bilal - was in the advanced stages of planning an attack on London's Heathrow Airport.

The raid in Pakistan last month led to the discovery of computer files that suggested British and US targets had been identified for attacks.

Pakistani intelligence officials told US television station CNN that 25-year-old computer expert Naeem Noor Khan, who was arrested in the Pakistan raid, told them there was a terror network in Britain.

He reportedly said he often relayed messages from Pakistan to the leader of the British cell, who was a top al Qaida operative.

Pakistani officials reportedly said the arrests that took place across Britain on Tuesday were a result of the intelligence they gathered.

Among those detained in the British raids was the senior al Qaida figure, they said.

The same sources told CNN that Khan's father worked for Pakistan's state-run airlines and had obtained five tickets - in his son's name - for travel between Pakistan and London during the past four or five years.

Police are continuing to question the 12 men, who are all thought to be of Asian origin, at Paddington Green police station, in London.

The men, aged between 19 and 32, were seized in a series of raids across the country on suspicion of being concerned in the commission, preparation or instigation of acts of terrorism.

Details of the plans to attack Heathrow were not divulged by Pakistani intelligence sources, neither was any time frame given.

But the sources said the plans were drawn up within the past year and have been updated during that time.

The intelligence officials revealed that Khan had used some trips abroad to evaluate targets, including some of the most famous buildings in New York and Washington.

Key financial centres in the two cities are currently on high "orange alert", following the alleged discovery of information on Khan's computer.

It is understood that Khan attended a terrorist training camp in Afghanistan in 1998 and worked alongside Khaled Sheikh Mohammed, an al Qaida boss who was arrested in Pakistan in April.

Police have until tonight to question the 12 men arrested in Britain before they have to apply to magistrates for an extension to the detention period of up to two weeks.

A 13th man, also detained on Tuesday in Willesden, north London, has since been released with no further action.

Meanwhile, British Muslims are feeling increasingly persecuted following the arrest of the 12 men, Islamic leaders warned last night.

Inayet Bunglawala, from the Muslim Council of Great Britain, said: "This is the latest in a series of high-profile raids since 9/11 where a large group of mainly young Muslim men are arrested amongst massive nationwide publicity.

"More than 500 people have been arrested and yet less than 100 have been charged.

"There is now a growing bitterness in the Muslim community. It seems the vast majority of these people are arrested amid very high publicity and yet when they are released it does not attract the same publicity.

"I think the police have a lot more to do in terms of working with the Muslim community and gaining their trust."

In the Commons, the law allowing foreign terror suspects to be jailed indefinitely without trial should be "replaced as a matter of urgency", a committee of parliamentarians said yesterday.

A report by the all-party Joint Committee on Human Rights increased the pressure on Home Secretary David Blunkett not to renew the emergency powers when they lapse in November 2006.