Britain's top spy, in the first public speech by a serving UK espionage chief, said today terrorists might hit the west again "at huge human cost" but that nuclear proliferation by states was a more far-reaching danger.
Secret Intelligence Service (SIS) chief John Sawers, in a address to the Society of Editors media group hosted at Thomson Reuters London offices, said the risks of failure in tackling proliferation by countries like Iran "are grim".
"Terrorism is difficult enough, and despite our collective efforts, an attack may well get through. The human cost would be huge. But our country, our democratic system, will not be brought down by a typical terrorist attack," he said.
"The dangers of proliferation of nuclear weapons and chemical and biological weapons are more far-reaching. It can alter the whole balance of power in a region," said Mr Sawers, whose century-old service is popularly known as MI6.
He added that intelligence failings on Iraq before the 2003 invasion showed "politicians and officials alike" how important it was that sources of information were rigorously evaluated.
Improving intelligence collection, co-ordination and analysis has been a major focus for Western governments since the September 11th, 2001, attacks and the 2003 Iraq invasion, events involving profound faults in preparedness.
A British inquiry in 2004 by a former top civil servant, Lord Butler, said it was a "serious weakness" that caveats from intelligence chiefs were not spelt out in a September 2002 dossier which set out the government's case for disarming Iraqi
Mr Sawers said: "The Butler Review following Iraq was a clear reminder, to both the agencies and the centre of government, politicians and officials alike, of how intelligence needs to be handled.
"Sources of intelligence have to be rigorously evaluated and their reports have to be honestly weighed alongside all other information. Those who produce it, and those who want to use it have to put intelligence in a wider context."
The Butler report urged steps to ensure "effective scrutiny and validation of human intelligence sources" and to make sure this was properly resourced and organised.
Reuters