Al Qaeda in the Afghan border area of Pakistan remains the greatest security concern to the West, but affiliates in Yemen, Somalia and North Africa show how diverse the threat has become, Britain said on Wednesday.
Home Secretary Theresa May said a member of Yemen-based al Qaeda in the Arabian Peninsula (AQAP), the group suspected of last week's air cargo bomb plot, had been arrested earlier this year in Britain where he had been planning an attack.
She also cited north Africa's al Qaeda in the Maghreb and Somali al Qaeda-linked group al Shabaab as organisations which wished to export violence to the West. Britons had already gone to Somalia to fight, she said.
"It seems highly likely ...that if left to their own devices we would eventually see British extremists, trained and hardened on the streets of Mogadishu, returning to the UK and seeking to commit mass murder on the streets of London," she said.
"Attacks might now come from foreign nationals or from British citizens recruited by al Qaeda, by its affiliate groups or by al Qaeda inspired groups".
Bin Laden's organization weakened
May said work by Pakistani, U.S. and British security agencies along with the coalition efforts in Afghanistan had made Osama bin Laden's al Qaeda organisation weaker than at any time since the Sept. 11 attacks on the United States.
"Al Qaeda is not the organisation it once was," she said in her first major speech on counter terrorism since the Conservative-Liberal Democrat coalition took power in May.
Despite this, the original group continued to be of most concern, while others had also sprung up.
"Most threats to the UK continue to come from the Federally Administered Tribal Areas of Pakistan," she said. "The threat we face comes not just from the old al Qaeda organisation. Many other terrorist groups now aspire to attack us."
British and U.S. officials have blamed AQAP for planting two parcels containing bombs on air freight from Yemen to the United States which were found last week. One of the bombs was discovered at an airport in central England.
AQAP is also blamed for the attempt by a Nigerian passenger to blow up a U.S. airliner on Christmas Day with explosives in his underwear.
May said the AQAP member arrested in Britain this year was accused of planning suicide bombings. He is due to go on trial next year.
"Our police and agencies have been working to disrupt AQAP operatives in this country," she said. "Threats such as these are likely to continue."
Last month Britain unveiled its new National Security Strategy and May said spending on counter terrorism policing would be more than 2 billion pounds in the next four years, with funding for greater firearms capacity to deal with an attack such as the deadly 2008 assault on the Indian city of Mumbai.
The previous Labour government brought in a series of draconian measures, such as extending the length of time a suspect could be held without charge and placing suspects under house arrest, and May said these would be reviewed.
She said the government wanted to rebalance security and liberty, saying Labour's attempts to integrate British Muslims with a focus on counter terrorism had only alienated many.
"We must not do the terrorists' job for them by either unduly increasing the fear of terror itself or by responding to the threat in a way which encroaches unnecessarily," said John Yates, Britain's most senior counter terrorism officer.