As the UK scrambled to find a bomb factory run by a cell of radical Islamist terrorists, people wondered how the 12 identified conspirators managed to get into the country in the first place. British authorities first pointed the finger at Pakistan, but Islamabad rejected that notion. Their representative in London accused British authorities of refusing to cooperate on background checks for the visas:

Earlier the High Commissioner had said that Britain was not doing enough. “It is at your end you have to do something more,” Wajid Shamsul Hasan said. Asked if there was a problem with the British system for student visas, he replied: “Yes. If they allow us to make inquiries first, if they ask us to scrutinise those people who are seeking visas we can help them. But the thing is they have their own regime — the regime that vets these people.”

Mr Woolas rejected the claim. “It’s naive to think that we don’t check. We do work very closely with the Pakistan authorities, indeed we’ve been criticised for doing so,” he told The World at One on BBC Radio 4.

The exposure of the plot to attack the UK forced the resignation of Britain’s highest-ranking counterterrorism official:

A desperate search was under way last night for the terrorist bomb factory from which a suspected al-Qaeda cell planned to launch a devastating attack in Manchester.

Hours after Britain’s most senior counter-terrorism officer resigned in disgrace, police operations were concentrating on a rundown block of flats east of Liverpool city centre. …

A dozen men are being questioned after raids that had to be rushed forward after Assistant Commissioner Bob Quick, the country’s most senior anti-terrorism officer, inadvertently disclosed details of the police plans.

Mr Quick resigned as head of Special Operations at Scotland Yard yesterday morning, admitting that his bungle “could have compromised a major counter-terrorism operation”.

The potential threat from the immigrants should have been considered. Ten of the 12 come from Pakistan’s Northwest Frontier Province, a hotbed of radical activity.  From the two stories, it seems as though Pakistani and British controls worked at cross-purposes, and AQ has discovered an easy way to get people into Britain while avoiding exposure through background checks.  The big question now facing British security is how many more sleepers AQ may gave gotten into their country.

The Times of London raises an interesting point.  Previously, terrorist groups concentrated on raising home-grown assets for their plans.  The London bombings in 2005 were not perpetrated by recently-arrived immigrants, but by three British natural-born citizens and one native of Jamaica.  The concern afterwards was that AQ would raise armies of terrorists within Western nations, which would bypass most counter-terrorism efforts.  This plot may indicate that AQ has not had much success in the past few years, or feels that infiltration still gives them a better chance.

Either way, this shows that AQ remains dangerous, and that it doesn’t take more than a few terrorists to create a great deal of havoc.  The UK managed to avoid an attack at the moment, but they may have more on the way.