Doctors among eight held in British car bomb plot

An eighth person was arrested yesterday and two doctors were among seven held in Britain in connection with a suspected al Qaeda plot to detonate car bombs in London and Scotland. One of the doctors, named by police sources as Bilal Abdulla, trained and qualified in Iraq in 2004, and the other, Mohammed Asha, qualified in Jordan the same year. Dr Asha's wife is among the seven suspects being held, police said.

Those arrested are linked to a plot to detonate two car bombs loaded with fuel, gas canisters and nails in London in the early hours of Friday, and an attack on Glasgow airport in Scotland on Saturday using a fuel-laden Jeep Cherokee. Police said the eighth person, a man, was arrested "at an undisclosed location". The BBC said he was arrested overseas.

Britain has seen a marked increase in terrorism-related attacks since the September 11 strikes on the United States and since it joined US forces in invading Iraq in 2003. However, previous assaults, including an attack on London's transport system in July 2005 which killed 52 people, have tended to involve radicalised, British-born Muslims, not educated attackers from overseas, security experts say.

In what authorities have described as a "dynamic investigation", police on yesterday cordoned off a hospital in Paisley, a town just outside Glasgow, and carried out several controlled detonations. The hospital, the Royal Alexandra, is where Dr Abdulla worked, staff said, and where it is also believed he is being treated for severe burns after taking part in the attack on Glasgow airport, when his vehicle was turned into a fireball.

Fearing further attacks, police banned cars and other vehicles from directly approaching airports and security measures were stepped up across the country as authorities kept the threat level at "critical", the highest rating.

A police source said the investigation was going very well and they expected to make more arrests. The source said the plot bore "all the hallmarks" of al Qaeda and there had been no warning of Saturday's attack on Glasgow airport.

The series of foiled and actual attacks pose a test for Prime Minister Gordon Brown, a Scotsman who replaced Tony Blair only last week and who has come under pressure from some quarters to change policy on Iraq and withdraw British troops.

Mr Blair was known for an aggressive stance on security and a foreign policy which strongly supported the United States in Afghanistan and Iraq. The bombers who struck London in 2005 said in videos they were punishing Britain for Mr Blair's policies.

Home Secretary (interior minister) Jacqui Smith said Britain was facing a "serious and sustained threat of terrorism" and urged the public to remain alert.

Addressing Parliament yesterday, she praised the security services for their quick work in rounding up suspects but said a threat remained.

On Saturday, police arrested the passenger and badly-burned driver of a Jeep Cherokee who had rammed the vehicle into the entrance of Glasgow's airport, causing a huge fireball.

The attack came 36 hours after police in London defused two Mercedes car bombs packed with fuel canisters, propane tanks and nails, parked in the heart of the capital's bustling theatre and nightclub district. The other arrests included a 26-year-old man and a 27-year-old woman seized on a motorway in northern England on Saturday, and a 26-year-old man in Liverpool on Sunday. All three were taken to London for questioning and police were given permission to hold them until July 7.

Dave Bryon, an aviation consultant and former director of British airline bmibaby, said attacks on airports posed a less controllable security threat than those targeting flights.

"When it's a landside incident you actually have very limited control, because not only have you got travellers, but you have people meeting and greeting, people dropping off ... and the taxi drivers and chauffeurs," he said.

The head of Scotland's administration, First Minister Alex Salmond, said he and Prime Minister Gordon Brown had been co-operating closely over the security alert.

"These are challenges we face north and south of the border and the Prime Minister and myself have been at one in making sure that the country won't be intimidated or stopped from going about its normal business by terrorist outrages," Mr Salmond told BBC radio.

Police and ministers said protective security measures would be stepped up across Britain, particularly at transport hubs.

"We will obviously be stepping up high visibility policing and we are working with other agencies, including British transport police, to help ensure security," a spokesman for London's Metropolitan police said.

He said extra police officers would be patrolling and carrying out more searches in areas where there were lots of people, including rail stations and airports.