'You can't get trained officers off the shelf'

Since the terrorist attacks in the United States in 2001 the three British intelligence agencies have enjoyed a huge boost to their funding in order to target al-Qa'ida followers.

But despite the increases in resources for MI5, MI6, and the listening centre, GCHQ in Cheltenham, the agencies argue that it is only now that they are starting to see the benefits of the extra money, because of the time taken to recruit and train applicants. New officers take up to a year before they are considered operationally useful.

A security source said: "It will take some time for extra funding to manifest itself into new intelligence officers. You can't just buy trained and ready officers 'off the shelf'."

Since the 9/11 attacks in America MI5 has grown from just under 2,000 staff to about 2,500. This is due to rise to 3,500 by 2008.

Since the July 7 attacks last year the Chancellor has announced an extra £85m on top of the existing £1.36bn budget.

MI5's efforts to track al-Qa'ida grew from 23 per cent of its operational effort in 2001-02 to 56 per cent by July 2005.

MI6, the Secret Intelligence Service, which deals with threats from abroad, is also involved in a recruitment drive, to boost its 2,000 officers to 2,500.