, the BBC reports.
The eighth detainee, the wife of one of the doctors arrested, is thought to be a lab technician at a National Health Service (NHS) hospital.
On Saturday, a car filled with crude gas cylinder bombs was driven into Glasgow's international airport where it burst into flames. The day before, two cars, also packed with gas cylinder bombs, failed to explode in front of a nightclub in London.
The two men who drove the Jeep into the Glagow airport are thought to have worked at the Royal Alexandra Hospital in Paisley, where one of them is being treated for burns. The suspects appear to all hail from different countries, including Iraq, Saudi Arabia, India and Jordan.
The disturbing physician-led plots are fuelling theories that al-Qaeda is using doctors to infiltrate the UK, using their status as physicians as a cover.
Britain -- and its tabloids (with headlines like "" and "") -- have reacted with horror to the thought that its hospitals are potential breeding grounds for terror cells.
More than a quarter of Britain's doctors are foreign-trained, according to (PDF) of NHS figures.
Prasad Rao, chairman of the British International Doctors Association, :
"It shocked me to hear that a doctor could remotely be connected to the people who are trying to kill and maim people for no reason.... A doctor's duty, even if he finds an injured terrorist, is to give medical help. You never knowingly help or assist an individual to kill and maim others. You take the Hippocratic oath and you do not discriminate on the basis of colour or gender or religion."