Londoners have been put on a pre-Christmas terror alert amid heightened police fears of fresh attacks by dissident republicans spelling "real danger" to members of the public.
The head of Scotland Yard's anti-terrorist branch, Deputy Assistant Commissioner Alan Fry, yesterday called on the public to "use your eyes and ears" as well as the confidential hot line number 0800 789 321, in a combined effort with police to reduce the risk.
The Met also launched a counter-terror advertising campaign in newspapers and on radio stations across the capital in a concerted drive to increase public vigilance after at least 13 attacks in Northern Ireland and London since February. There have been three attacks on high-profile targets in London since June.
Mr David Veness, assistant commissioner in charge of specialist operations, said the campaign was best understood "by seeing events in Northern Ireland and mainland Britain as one series of events".
In addition to attacks on MI6, Hammersmith Bridge and the rail track between Acton and Ealing Broadway stations, Mr Veness disclosed there had been more than 100 threatening telephone calls since last December designed to cause disruption and inconvenience to the travelling public.
Mr Veness said the police had a duty to assess the content of each call, seeking to avoid disruption while striking the difficult balance "between normality and safety", often with little time available.
He said a range of attack methods had been used, "some designed to kill members of the security forces" while others had been "completely reckless as to casualties amongst members of the public".
Previous attacks included improvised explosive devices at military installations, including victim-initiated or "booby-trapped" bombs, car-bombs, bombs on railway lines and the use of rocket-propelled grenades. The police, he said, had reasonable grounds to believe the dissidents were "in possession of both home-made and manufactured explosives and incendiary devices, assault weapons and guns.
"In our view, any use of battlefield weapons and high explosives in any location to which the public have free access, a city centre being a classic example, is both reckless and likely to cause injury and death."
Mr Fry appealed to charities, the media and hospitals, the most likely recipients of threatening calls, to do their best to record them accurately as this helped enormously with the assessment of each call. He also asked the owners of commercial and residential property, motor traders, landlords and hoteliers to come forward with any information about suspicious persons or activities.
Urging people to be "vigilant and suspicious", Mr Fry appealed to those with CCTV equipment to keep them well maintained and to retain videos for 31 days.