The Indian doctor taken into custody in Liverpool last Saturday in connection with the aborted car bomb attacks in London and Glasgow has been identified as Sabeel Ahmed from Bangalore, media reports said on Wednesday.
Both Ahmed and another Indian doctor detained in Australia, Mohammed Haneef, also from Bangalore, had worked together in Halton Hospital in Cheshire in 2005.
Ahmed is still working there, the reports said.
Security experts are considering relaxing the official estimate of the terrorist threat to the UK from 'critical' to "severe" even as six people taken into custody over the failed car bombings are being questioned at London's Paddington Green police station on Wednesday.
A seventh man, Khalid Ahmed, remains in hospital after the Glasgow attack. Haneef, being questioned in Australia, is the eighth man allegedly linked to the plot.
Others are Dr Mohammed Asha, apparently Saudi-born but Jordanian educated and a feted neurologist, considered the ring leader of the Al-Qaeda 'sleeper cell' for the latest terror campaign against the UK transport and leisure assets, his wife Marwah; Dr Bilal Abdulla, an Iraqi who worked at the Royal Alexandra Hospital in Paisley; and two unnamed Saudi junior doctors also working at the Royal Alexandra Hospital in Paisley.
According to a report in the Daily Mail, a senior Al Qaeda leader in Iraq gave a warning about the attacks in Britain weeks before.
Canon Andrew White, an Anglican priest working in Baghdad, said an unnamed Al Qaeda leader told him: 'Those who cure you would kill you.'
'He talked to me about how (his group) was going to destroy British and American targets. He told me that the plans were already made and they would soon be destroying the British.'
Detectives investigating the NHS car bomb plot were on Wednesday examining an international network of e-mails and phone records.
Al Qaeda's Abu Musab al-Zarqawi may have ordered the bombers to go to Britain as a 'sleeper cell,' the report said.
Police have seized computers from hospitals in Glasgow, Stoke-on-Trent and Liverpool.
They are examining a theory that suspects planned the attacks in cyberspace while working at NHS hospitals.
The development was revealed as Scotland Yard sent a senior counter-terrorism investigator to Australia where one of the suspects is being held.
It also emerged on Wednesday that some of the eight suspects being questioned were known to Mi5, the British intelligence service, before the attacks took place. A small number had appeared on the Mi5 database though sources said they had merely 'crossed the radar.'
Anti-terrorist detectives are working on numerous leads thrown up by evidence -- notably mobile phones -- recovered from the car bombs left in Haymarket and Cockspur Street in London last Friday.
Police believe they have arrested the main players in the conspiracy though they cannot rule out the possibility that others are still at large.
The security services believe Al Qaeda sent one or two extremists to Britain with instructions to recruit a network of terrorists within the NHS. One of those being held, Iraqi doctor Bilal Abdulla, 27, had extremist links in Baghdad where he worked until a year ago.
Abdulla had been disciplined for spending too much time on the internet at the Royal Alexandra Hospital in Paisley outside Glasgow.
There were reports in the US that the Iraqi doctor was recruited two years ago by Al Zarqawi, who was killed in Iraq last year.
Abdullah was one of two people in the blazing jeep that crashed into the Glasgow airport terminal last Saturday. The driver of the jeep was another doctor, Khalid Ahmed, who suffered 90 per cent burns and is not expected to survive.
The two men are now believed to have left the two Mercedes car bombs in London. Police have established that they returned to Glasgow using trains and coaches.