A Scottish hospital is now at the centre of the investigation into the attempted terrorist attacks in London and Glasgow.

Previous investigations by the security services into suspected terrorist cells have focused on mosques, universities and Islamic charitable organisations. However, this time the common link appears to be a hospital.

For the second consecutive day yesterday the Royal Alexandra Hospital in Paisley was the subject of intense forensic examination.

As information began emerging yesterday about the men suspected of carrying out the Glasgow Airport and London car bombs one detail stood out: around half of the men are confirmed as doctors, and a further two had links to the Paisley hospital.

One of the men alleged to be involved in the attack on Glasgow Airport was named yesterday as Bilal Abdulla, an Iraqi who worked at the Royal Alexandra as a locum doctor.

He was the passenger in the Jeep which was driven into the terminal building at the airport, just two miles from the hospital. The Jeep managed to infiltrate security by tailgating a taxi as it passed through the barrier.

According to the General Medical Council, Dr Abdulla graduated in Baghdad in 2004 and was working in a supervised NHS role.

It is thought Dr Abdulla was living in a house in Neuk Crescent, Houston, Renfrewshire, which police officers raided early on Sunday.

A taxi driver told the BBC he recognised Dr Abdulla, who he claimed he had driven to work from a house in Neuk Crescent to the hospital on a number of occasions. He said: "He was just a regular man: we talked about hillwalking, women, Rangers and Celtic, that kind of stuff."

Little else is known about Dr Abdulla, except that he first registered with the General Medical Council in August 2005. He is being held in Govan Police Station in Glasgow, but will be transferred to the high-security Paddington Green Police Station in central London.

Even less is known at this stage about the driver of the Jeep, who suffered 90% burns during the airport attack and who is critically ill at the Royal Alexandra, where he is being kept under armed police guard. In addition to Dr Abdulla and the driver of the Jeep, a further two men, aged 25 and 28, were detained from the staff quarters of the Royal Alexandra on Sunday night and are now being held in Govan in connection with alleged offences under the Terrorism Act.

Police would not comment on whether either of these two men, who are not believed to be Scottish, were doctors at the hospital.

Nevertheless, the authorities did confirm yesterday that another of the suspects, who was arrested along with his wife heading north on the M6 motorway on Saturday, was also a doctor.

Dr Mohammed Asha, 26, who worked at North Staffordshire Hospital, in Stoke-on-Trent, and lived in nearby Newcastle-under-Lyme.

Dr Asha, who is thought to be Palestinian, trained in Jordan and is being held with his 27-year-old wife at Paddington Green.

It was reported last night that Dr Asha may at some point have worked from an office within the accommodation block at the Royal Alexandra Hospital. That area was cordoned off yesterday as bomb disposal officers carried out two controlled detonations.

As well as Dr Asha and his wife, a third man is also being held at the The 26-year-old was arrested in the Lime Street area of Liverpool on Saturday evening and is a doctor from Bangalore in India who works at Halton Hospital in Cheshire, according to the Muslim News.