In a speech he said the main national security threat was from Al Qaida and its associated groups

Jonathan Evans, the new head of Britain’s security service MI5, warned that Russian and Chinese spies were active in the UK and spoke about perseverance in the fight against international terrorism, in a rare public speech at the Society of Editors conference in Manchester on 5 November 2007.

In the speech he said: ‘The main national security threat that we face today is from Al Qaida and its associated groups.’

He said the root of the international terrorism problem was the extreme ideology underlying violent groups such as Al Qaida.

Evans upped the number of violent individuals planning attacks against the UK to 2,000. His predecessor Eliza Manningham-Buller estimated the number at 1,600 one year earlier.

“As I speak, terrorists are methodically and intentionally targeting young people and children in this country. They are radicalising, indoctrinating and grooming young, vulnerable people to carry out acts of terrorism.

Jonathan Evans, the new head of Britain's security service MI5

‘This growth, which has driven the increasingly strong and coordinated government response, is partly because our coverage of the extremist networks is now more thorough. But it is also because there remains a steady flow of new recruits to the extremist cause,’ he alleged.

The director general said conspiracies were increasingly being driven from overseas, particularly East Africa, Iraq and the tribal regions of Pakistan, often using young British citizens to mount the actual attacks.

And he warned: ‘We can see that the threat from Al Qaida related terrorism goes well beyond the UK.’

Attacks were becoming more sophisticated in their planning, he said, calling for a collective effort from Government, faith communities and wider civil society to tackle the situation. He said intelligence alone would ‘not in itself provide certainty.’

“The main national security threat that we face today is from Al Qaida and its associated groups.

Jonathan Evans, the new head of Britain's security service MI5

Evans also lamented the presence of Russian and Chinese intelligence officers operating in the UK, despite the end of the Cold War: ‘A number of countries continue to devote considerable time and energy trying to steal our sensitive technology on civilian and military projects, and trying to obtain political and economic intelligence at our expense. They do not only use traditional methods to c collect intelligence but increasingly deploy sophisticated technical attacks, using the internet to penetrate computer networks. It is a matter of some disappointment to me that I still have to devote significant amounts of equipment, money and staff to countering this threat.’

The head of Britain’s security service made one other horrifying prediction: ‘As I speak, terrorists are methodically and intentionally targeting young people and children in this country. They are radicalising, indoctrinating and grooming young, vulnerable people to carry out acts of terrorism.’

‘This year, we have seen individuals as young as 15 and 16 implicated in terrorist-related activity,’ he added.