It's really about Pakistan and the countless connections between Britain and its former colony:
Despite the efforts of Pervez Musharraf, the president of Pakistan, to clamp down on Islamic extremists, scores of young British Muslims are known to have received terrorist training at Taliban-controlled madrassas in Pakistan.
An estimated 60,000 youngsters travel from Britain to visit relatives in the country every year, and it is a monumental security challenge to identify the dozen or so who might be susceptible to radicalisation.
All you need is a handful. And Bush's inept occupation of Iraq has only made matters worse, providing a critical training base for mass murder.