The man suspected of masterminding the 7 July terror attacks on London was directly linked to another major plot to bomb the capital that was foiled last year, the head of MI5 has admitted.
In evidence to the Commons Intelligence and Security Committee on the July bombings, Eliza Manningham-Buller is understood to have admitted that Mohammad Sidique Khan had 'direct' contact with an individual known to have been involved in the earlier plot. The foiled attack is thought to have involved the use of a vehicle full of home-made explosives.
Until now, Khan was said to have only an 'indirect link' to other terrorists, with reports last month revealing he was recorded speaking to a UK-based terrorist suspect as part of a top-level surveillance operation.
However, police sources have distanced themselves from more recent reports that Khan's accomplices in the London bombings - Shehzad Tanweer, 22, Jermaine Lindsay, 19, and Hasib Hussain, 18 - had been watched by intelligence officers a year before they killed 52 people on tube trains and a bus.
The increased profile of Khan will again raise questions about intelligence failures leading up to the London bombings. Manningham-Buller is understood to have told the committee - which holds its hearings in secret - that the London bombings were not a result of an 'intelligence failure', referring instead to an 'intelligence gap' which allowed the 7 July terrorists to carry out the attack.
Security sources point to the fact that since the London bombings MI5 has successfully managed to thwart 'a number' of suicide terrorist attacks targeted at the capital's infrastructure and popular shopping locations.
The revelation comes amid ongoing concern over the practice of radicalised Muslims infiltrating Britain after visiting conflict regions abroad.
A Metropolitan Police source identified the Balkans, Chechnya, Afghanistan and more recently Iraq. Last month Andrew Rowe was jailed at the Old Bailey for terrorist offences after spending over a decade travelling the globe in pursuit of jihad.
British security sources believe that there are some 70 British jihadists fighting in Iraq, yet little information of any organised network has emerged.
Antony Barnett and Mark Townsend