British intelligence helped foil an al-Qaeda plot to blow up the New York subway just five days before it was due to go ahead, it can be disclosed, as Abid Naseer, a suspect in the case, faces an extradition hearing in London.

The suicide attack, planned to mark last year’s anniversary of the September 11 attacks was to be the biggest plot in the US since 2001.

Three men were allegedly planning to strap bombs to themselves and attack the underground with coordinated explosions planned to emulate those on London five years ago.

The plot was only foiled when one of the men emailed an al-Qaeda fixer in Pakistan to ask for advice on mixing chemicals, security sources on both sides of the Atlantic have told The Daily Telegraph.

Previous reports had suggested that the men were under surveillance by the FBI for some time before their planned attacks but sources now say the plot came close to success.

It is understood that the fixer – who used the names Sohaib, Ahmad and Zahid – is now in custody in Pakistan but despite repeated approaches from The Daily Telegraph, the authorities there have refused to say where he is held or whether he has been brought before a court.

He was also the man behind an al-Qaeda plot to blow up shopping centres in Manchester last Easter which led to the arrest of 12 Pakistani students.

Two of the students had apparently met Sohaib, a low level al-Qaeda commander, in Peshawar, Pakistan, in November 2008.

MI5 and Greater Manchester Police launched a huge surveillance operation in February 2009 and found that one of the students, Abid Naseer, had sent an email to Sohaib in which he said they were planning a “nikah” or wedding, thought to be code for an attack.

No explosives were found during the raids but the students were sent to immigration custody and eventually all except Naseer agreed to return to Pakistan.

He faces an extradition hearing this week after the US authorities alleged he was also connected to the plot to blow up underground trains in New York.

The New York investigation began on September 6 2009 when an Afghan-born man brought up in Queen’s, New York also began emailing Sohaib.

Najibullah Zazi was desperate to be reminded of his bomb-making instructions from a visit to Pakistan a year earlier.

He had already bought hydrogen peroxide and other bomb-making chemicals but wanted to know what proportions to use.

Alarm bells began ringing at America’s National Security Agency and as he hired a car and drove towards New York three days later, an FBI operation was launched to track him.

The network was uncovered as a result of work by MI6 to track down associates of Rashid Rauf, the al-Qaeda commander thought to be in “day to day” control of a plot to blow up trans-Atlantic airliners with home made liquid bombs.

The terrorist leader, who was brought up in Birmingham, is also thought to have been involved in the July 7 and July 21 attacks.

(Source: Telegraph UK)