Police from London are investigating an unprecedented 70 terrorist-related cases in Britain and the rest the world, with new threats constantly emerging, a senior officer said on Friday.
Speaking five days before the first anniversary of the July 7 London bombings, Peter Clarke, head of the anti-terrorist branch at the Metropolitan Police, said the information being uncovered was "very sinister".
"The level of counter-terrorist investigations has intensified during the past 12 months," Clarke told a press briefing, assessing the security situation since the deadly suicide attacks on London's transport network.
"There has been an unrelenting demand for intelligence to be investigated and operations conducted to arrest suspects or disrupt terrorist activity when judged to be appropriate," he said.
"The Metropolitan Police anti-terrorist branch have around 70 current investigations spanning London, the UK and the globe," said Clarke.
"That is the nature of what we face. The defence of the capital often starts many thousands of miles away."
London's police force was running at full capacity to handle the record number of active investigations.
"There is a lot of intelligence to be investigated -- some of it is very sinister," the counter-terrorist officer said.
"It is a very, very concerning intelligence picture."
Clarke said the changing nature of the threat meant police had to intervene to thwart attacks much sooner than they would have in previous years. Sixty people are currently awaiting trial in Britain for crimes linked to terrorism.