London al Qaeda link

A London man is to be questioned over suspicions that he played a key role in the Madrid bombings.

Abu Qatada is described as Osama bin Laden's "ambassador" in Europe and is regarded as one of the most dangerous Islamic terrorist leaders being held in Britain.

He is said to be connected to one of the men held over the Spanish train bombings which left 200 dead.

Anti-terror police will quiz the cleric, who is being held at Belmarsh prison, about his links with that man and two other Moroccans arrested in Spain after Thursday's attacks.

One of the three is said to be an associate of the head of al Qaeda in Spain, Imad Eddin Barakat Yarkas. Syrian-born Yarkas - who has been charged with helping the September 11 hijackers - has visited Britain 20 times and is known to have met Qatada.

Police will want to know if any of the arrested Moroccans have visited Britain, met Qatada or received instructions from him. One Spanish security source said: "It can't all be coincidence that Qatada's name is linked to suspects in Germany, France, Italy, Britain, Belgium as well as Spain."

Suspicions over Qatada's involvement came as London was placed on a dramatic new terror alert in a bid to prevent a repeat of the bombings in Madrid. Dozens of undercover police have been deployed on the Underground to spot suspicious packages and potential suicide bombers.

A major new poster campaign will urge the system's three million daily passengers to report abandoned bags.

Met Commissioner Sir John Stevens said he would not hesitate to order tanks and troops on the streets if he believed they were needed to deal with the terrorist threat.

The three men arrested at the weekend in Spain included Jamal Zougan. He was named in September by a judge who indicted Bin Laden and 34 other alleged members

of the al Qaeda network for trial for the 11 September attacks.

Zougan was held with Mohamed Bekkali, 31, and Mohamed Chaoui, 34, on suspicion of involvement in the sale and falsification of a mobile phone and SIM card found in an unexploded bomb on one of the trains. The bombers used mobile phones to detonate the devices.

Police are trying to establish if there is a link between the men and Qatada who was regarded as one of Britain's most wanted men until he was caught 18 months ago.

Born Omar Mahmood Abu Omar, the former cleric at the Finsbury Park Mosque is now being held in Belmarsh on the orders of Home Secretary David Blunkett. Though he has always denied involvement in terrorism, he fled his semi-detached house in Acton where he lived with his wife and children and went to ground hours before laws allowing his detention came into force.

Qatada, a 43-year-old Palestinian who has nine aliases and gave three different dates of birth, was granted asylum in Britain 10 years ago and remained despite having been given a life sentence in Jordan for carrying out bombings there.

Qatada is well known for his hardline views, refusing to condemn the September 11 attacks.

Under powers brought in after September 11 which allowed the security services to seize assets linked with terrorism, a total of £180,000 was found in his bank account.

During his appeal against detention, which he lost in January, a dossier submitted to the tribunal by Mr Blunkett stated the intelligence services believed he had met Bin Laden.

The dossier also included evidence that videos of his sermons were found in the Hamburg flat used by three of the September 11 hijackers, and he gave encouragement to the terrorists.

It has also emerged that shoebomber Richard Reid was a frequent visitor to his meetings at the Four Feathers Youth Club in Baker Street.