But senior Al-Qaeda leaders still hope to recruit Britons to carry out bombings in the country, MI5 director-general Jonathan Evans was quoted as saying by six British newspapers.

A British security official, who spoke on condition of anonymity since the person was not authorised to speak publicly, confirmed the reports of Mr Evans' comments were accurate.

MI5 said it was the first-ever media interview by a serving director in the agency's 100-year history. Evans gave the interview on Tuesday.

He said the persistent surveillance of around 2,000 targets, and a string of successful prosecutions of terrorists in Britain's courts in recent years, has forced many suspected extremists to restrict their activities, the newspapers reported.

'There have been 86 successful convictions since January 2007 of whom approaching half pleaded guilty, which has had a chilling effect on the enthusiasm of the networks. They're keeping their heads down,' Mr Evans was quoted as saying. 'We have probably seen fewer late-stage attack plans over the last 18 months.'

But he said terrorists in Britain and overseas retain the ability, and desire, to mount attacks like the 2005 suicide bombings, when four Britons killed 52 commuters on London's transit network in a series of coordinated suicide bombings, according to the reports.

'The strategic intent of the al-Qaida core, in Pakistan, is to mount attacks in the UK, and their model is to use British nationals or residents to deliver the attacks,' Mr Evans was quoted as telling The Times of London and five others newspapers.

The MI5 chief said he believes Osama bin Laden is likely still alive, but now acting only as a 'symbolic figurehead' for Islamic extremists, according to the reports.

Mr Evans granted the interview to mark the centenary year of Britain's domestic spy agency, which was set up in October 1909 to investigate fears that German spies were attempting to gain intelligence on Britain's naval ports, MI5 said.

Mr Evans also said the financial crisis could prompt new security risks and a surge in economic espionage, according to the newspaper reports.

Mr Evans said around 2,000 people in Britain are actively involved in terrorism. Countless more are involved in 'fundraising, helping people to travel to Afghanistan, Pakistan and Somalia. Sometimes they provide equipment, support and propaganda,' he was quoted as saying.

The spy chief said those seeking to radicalize young Muslims are guilty of a form of child abuse, and predicted extremists will likely attempt to exploit Israel's military attacks on the Gaza Strip as a propaganda tool, according to the reports.

Mr Evans was quoted as saying London's 2012 Olympic Games could be 'potentially a very big target' for terrorists, and said his agency has increasing concern about activity among a small number of dissident Irish Republicans, the newspapers reported.

'There has been a series of determined attempts to kill a police officer in Northern Ireland,' Mr Evans was quoted as saying. -- AP