Intelligence chiefs fear that terrorists would attack London or another western capital with bombs, the Sunday Telegraph reported.

Security sources disclosed that most intelligence agencies held that a chemical, biological, radiological or nuclear attack (CBRN), using a so-called dirty bomb, is inevitable, said the report.

The warning came three weeks after 250 police officers raided the home of two Muslim brothers in west London, believing mistakenly that they were related to the making of a chemical bomb.

The raid followed growing concern among Britain's intelligence and security hierarchy that if a CBRN attack took place in the city of London, it would devastate the country's economy and severely damage the economies of Europe and America.

It also appeared that the police had been warned of the activities in the hometown of the July 7 bombers almost two years before the suicide attacks last year.

Senior officials say that the 9/11 attacks "freed the mind" of intelligence agencies analyzing the capabilities of terrorists, and it would be "reckless" to underestimate the "capability and intent" of terrorist groups such as al-Qaida.

The Sunday Telegraph said the claim by British Home Secretary John Reid that there are currently 20 active terrorist conspiracies underway in Britain is now regarded as a "modest" assessment, and the actual number is significantly more.

It is believed that the number of terrorist suspects believed to be operating in Britain is more than 1,200, almost 400 more than the figure quoted in the intelligence and security committee report on the July 7 attacks published last month.

Nonetheless, security sources admit that they do not know the full scale of the terrorism problem currently facing Britain.

Source: Xinhua