The most acute peacetime threat that Britain has faced in a century, and they're only getting around to it now:

British security officials suspect that at least 4,000 people are involved in terrorism-related activities in Britain and that Al Qaeda's "deliberate campaign" against Britain poses the "most immediate and acute peacetime threat" to the nation in a century, the head of Britain's domestic spy agency said yesterday. "Terrorist attacks we have seen against the UK are not simply random plots by disparate and fragmented groups... The majority of these attacks, successful or otherwise, have taken place because Al Qaeda has a clear determination to mount terrorist attacks against the United Kingdom."... Evans said that security agents are watching about 2,000 suspected terrorists in Britain and that they suspect "there are as many again that we don't yet know of." The remarks by Evans, who took over as head of MI5 in April, amplified the threat described a year ago by his predecessor... who said agents were tracking 1,600 people in at least 200 cells.

The attacks are planned overseas by AQ leadership, but are implemented by British citizens. The number of British citizens willing to participate is growing rapidly as the age of those citizens is quickly decreases:

Teenagers as young as 15 are being groomed to carry out terrorist attacks in Britain and al-Qaida sympathisers are hatching plots in a growing number of foreign countries against targets here, the head of MI5 warned yesterday. In his first public speech, Jonathan Evans described the threat posed by al-Qaida-inspired extremism as "the most immediate and acute peacetime threat" the security service had faced in its 98-year history. The threat, he emphasised, had its roots in ideology, making it all the more important that the response must not be indiscriminate.

Absolutely. What MI5 has to do is be very gentle and discriminant with 4,000 people - because those kinds of numbers can be easily handled by the kind of methodological and soft multiculturalism that has served Britain so well thus far. You know what? Even better. They should withdraw from the world and turn inward - because then AQ will stop coming for them. The Terrorism Research Center has the white paper of the report.

References:
* Al Qaeda threat grows in UK, spy chief says [WaPo]
* 'Thousands' pose UK terror threat [BBC]
* Al-Qaida recruiting teenagers to attack targets in Britain, warns MI5 chief [Guardian]
* TRC White Paper: Utilizing Terrorism Early Warning Groups to Meet the National Preparedness Goal [TRC]

Previously:
* We're Going To Miss Westminster Abbey - British Spy Chief Calls Out BBC For Shoving AQ Propaganda Down Kids' Throats, Blaming US For 9/11
* We're Going To Miss Westminster Abbey - Sharia Courts Established In Britain
* If Britain Won't Stop Radical Islam, Why Should Radical Islam Stop Being Radical?