Al Qaeda threat to blow up BA jets

British intelligence discovered a direct threat that al Qaeda intended to attack a British Airways plane flying to or from Saudi Arabia, it emerged today.

Officers with MI6 were able to establish that there was a real and present danger after intercepting a series of signals in the Gulf region.

That information was immediately passed on to the airline and was the main reason why yesterday, BA announced that it was suspending all flights to and from Saudi.

At the same time as the British intelligence warning came another alert from Saudi security officials about plans for an attack by Islamic militants on a BA plane on the ground at Riyadh airport.

They told MI6 that they had discovered a detailed map in a car after a series of gun battles between security police and suspected extremists in the suburbs of the capital.

In one battle, three policemen were killed and several suspects captured. Local officials say the gun battles mark a departure by al Qaeda, which has broken up into smaller units seeking targets of opportunity.

The plan uncovered by the Saudis clearly indicated that a BA Boeing 777, which can carry up to 300 passengers, was a terrorist target as it waited on the ground at Riyadh.

The latest alert follows the cancellation of BA flights into Nairobi for several days in May after what has been described as a "precise indication" that a British Airways 747 jumbo would be attacked as it came into land.

The grounding of all BA flights from both Riyadh and Jeddah has left up to 50 crew members stranded.

Allied ships patrolling the Gulf off the coasts of Tanzania and the Seychelles have recently picked up a number of signals indicating that al Qaeda is trying to stage a major attack on British and American interests across the region.

British experts in the Gulf now believe that Osama bin Laden's original al Qaeda cells have split up and are operating in small cells throughout the Gulf region and east Africa.

They believe that Bin Laden is still alive, and moving between Baluchistan and the Northern Tribal territories in northern Pakistan.

According to one report, he has suffered a severe wound which has left one of his arms almost completely paralysed.

His second-in-command, Dr Ayman al-Zawahiri, is known to be particularly active in trying to organise fresh operations and win more recruits.

A British military source in the Gulf said a few weeks ago: "Al Qaeda has been badly disrupted."

He added that he believed that al Qaeda fighters have found refuge in a number of the Gulf States such as Dubai since their defeat in Afghanistan two years ago.

In the past few days, a number of al Qaeda cells have been identified inside Iraq, made up of foreign fighters being smuggled in from Jordan and across the Turkish border.

The grounding of the services in Saudi came after BA announced plans to fly into the Iraqi city of Basra via Kuwait twice a week, with the option of resuming flights to Baghdad later this year.

No date has been given for the Basra service to begin, and the plan may now be put on hold.

The growing signs of instability in Saudi Arabia are beginning to worry officials in London and Washington. The Saudis say they have arrested senior commanders in the al Qaeda network, but western officials have yet to be convinced.

Since the last Gulf war in 1991 and the recent conflict in Iraq, Saudi Arabia has moved from staunch ally to regional obstacle. In the Iraq war, British and American planes based in Saudi Arabia were severely restricted, and a few days into the conflict, Saudi and Turkish air space was closed to overflights by Tomahawk cruise missiles.

The grounding of BA flights to and from Saudi Arabia has not been directly linked to the arrest in New Jersey of the arms dealer Hemant Lakhani, a British citizen of Indian descent, who is accused of trying to smuggle ground-to-air missiles into the US to be sold to Islamic extremists.

If the militants in Saudi Arabia had the weapons he was trying to sell, the SA-16 Igla missile, the threat to British and other western commercial aircraft would increase dramatically.