Terror plot: 'NHS bombers' left 'suicide' note

Their message allegedly reveals the motives behind the attack and claims that the men in the car intended to blow up the vehicle, according to US news channel CNN.

However, a Met Police spokesman said: "We would not discuss something like that." Police also refused to say where the note was found or its exact contents.

According to US intelligence the plot failed because a medical syringe used as part of the firing mechanism failed. The alleged mastermind of the terror plot and others in the terror cell are doctors working in the NHS.

Police have also revealed there are family links between three of the eight people arrested while an Indian newspaper claims two of the men held are brothers.

Khalid Ahmed, who was arrested at Glasgow Airport - and Sabeel Ahmed, who was held in Liverpool, are related, The Times Of India said. Both men are doctors, in Paisley and Runcorn respectively.

It's also alleged Kafeel Ahmed, who drove the flaming Jeep into the airport terminal, was the maker of all three car bombs.

The origins of the plot have been traced to the idyllic surroundings of Cambridge.

Iraqi doctor Bilal Abdulla, believed to be the link man between all eight suspects, is thought to have been introduced to at least four of them while living in the university city.

Dr Abdulla, 27, is reported to have been recruited in Iraq by Al Qaeda mastermind Abu Musab al-Zarqawi and given instructions to form a "sleeper cell" of fellow doctors after securing a job in the NHS.

He spent several periods in Cambridge between 2001 and 2006, living near relatives in the city while improving his English.

There he is believed to have met neurosurgeon Dr Mohammed Asha, who worked at Addenbrooke's Hospital and who remains under arrest together with his wife Marwah.

It was also reported that another suspect, Dr Sabeel Ahmed, 26, had a brother studying at Cambridge University at the time Dr Abdulla lived there.

Dr Ahmed is the uncle of fellow suspect Dr Mohammed Haneef, 27, who is being held in Australia.

Police have searched former addresses of Dr Abdulla in Cambridge and interviewed members of the mosque where he worshipped as they tried to build up a picture of the connections between the eight suspects, and of how the alleged cell may have come together.

Shiraz Maher, a former Cambridge University student who met Dr Abdulla through the city's Abu Bakr Siqqid Mosque, said: "He supported the insurgency in Iraq and cheered the deaths of British and American troops.

"He was very strict about his religion and at one time he was sharing a flat with a guy who was a Muslim but didn't pray five times a day and played the guitar.

"Bilal found it an absolute outrage and he told him 'you'd better start praying five times a day and you'd better stop playing the guitar'.

"He put on a DVD of al-Zarqawi beheading one of the hostages and said: 'Look - if you don't, this is what we do. We slaughter'."

The national terror threat level was reduced from critical to severe yesterday for the first time since the attempted attacks on London and Glasgow Airport.

Home Secretary Jacqui Smith said there was "no intelligence" to suggest another attack was imminent.

Prime Minister Gordon Brown vowed to tighten vetting procedures for foreign workers. All eight of the alleged plotters had come to the UK from the Middle East and India.

However, tighter procedures would have had little effect on alleged ringleader Dr Abdulla, as sources in Scotland said he came into the country using a British passport, having been born in the UK when his father worked here in the 1970s.

His British credentials would have made him far less likely to attract the attention of the security services.

As police continued to question seven suspects, with an eighth lying critically ill in hospital, details of Dr Abdulla's movements within the UK over the past six years came to light. From 2001 until 2006 he made several trips here to improve his English, living in Cambridge, where he has an uncle and grandparents.

In 2005 he is believed to have been introduced to Jordanian doctor Mohammed Asha, 26, who spent two short periods working at Addenbrooke's Hospital in the city after being given glowing references by his medical school in Amman.

Dr Asha and his wife Marwah, 27, later moved to Newcastle-under-Lyme in Staffordshire.

Channel 4 News reported that Dr Sabeel Ahmed, originally from Bangalore in India, who was arrested in Liverpool at the weekend, had a brother at Cambridge through whom he may have met Dr Abdulla.

Dr Abdulla was living in a flat in the city's Milton Road and also worked on the checkout at a Staples-office supplies store, when he is said to have met Sabeel Ahmed.

Channel 4 News quoted an unnamed friend of the two men saying: "Sabeel and Bilal were like clowns, loud and funny, cracking jokes all the time. Sabeel used to pay flying visits to the city."

Sources in India also claimed Dr Abdulla had later been a member of the same "Muslim Rights group" as Dr Haneef, 27, and Dr Ahmed, 26, in Liverpool.

The remaining three suspects, Dr Kafeel Ahmed, who suffered severe burns in the car bomb attack on Glasgow Airport, and two unnamed medics aged 25 and 28, all worked with Dr Abdulla at the Royal Alexandra Hospital in Paisley.

Dr Abdulla was born in Aylesbury, Buckinghamshire in 1979, and spent the first few years of his life in impeccably middle-class surroundings.

His father Talal was working as a rheumatologist in hospitals in Buckinghamshire and the family lived in a smart detached threebedroomed home in nearby Monks Risborough at the time. By 1982, when Dr Abdulla's sister Hiba was born, the family had moved to Chelsea.

Police sources said they believed all of the key members of the alleged plot had been arrested, and as a result the Joint Terrorism and Analysis Centre decided to lower the nation's threat level.