In a world first, the system will detect explosives, liquids and bomb-making components even if they are hidden under clothing or inside rucksacks.

Canary Wharf in the Docklands area of the capital is home to HSBC, Barclays and Bank of America and regarded as a prime target for Al-Qaeda; the IRA bombed a nearby target in 1996.

The system at Canary Wharf — part of a wider anti-suicide-bomber project codenamed Nemesis — uses “superhuman vision” to “see through” people as they enter their offices and shopping areas. Monitors attached to hidden CCTV cameras can scan from long distances for knives, guns and even drugs.

The Sunday Times was invited to the system’s underground control room, which is reminiscent of the bunker in Dr No, the Bond movie. It is bomb-proof and has secure radio communications to patrol officers on the ground and to Scotland Yard and other emergency services.

It is designed to withstand the impact of an airliner hitting Canary Wharf Tower, and has food rations and its own supply of air and water. The room is dominated by five wall-to-wall television screens, each split into a patchwork of smaller screens that relay footage from hundreds of CCTV cameras around the site.

Richard Kemp, a former senior member of the government’s Joint Intelligence Committee, is in charge of the surveillance operation. He headed the British intelligence team responsible for domestic and international terrorism.

Kemp said Nemesis aimed to protect the public without being intrusive or harmful.

“We will be the first people in the world to use it in public areas. It is a big leap forward in dealing with the growing threat of person-borne suicide attacks,” he said.

However, it is likely to reinforce concerns that personal privacy is being too lightly sacrificed.

Last week Richard Thomas, the information commissioner, warned that Britain was “waking up to a surveillance society”, with people being tracked throughout their lives.

The system is manufactured by ThruVision, an Oxford-based company. It relies on the emerging science of terahertz waves — or T-waves — which provide more detailed images than x-ray scanners. Scientists say the waves can distinguish Semtex from modelling clay and cocaine from sugar.

T-waves occupy part of the electromagnetic spectrum between radio waves and infrared light. They are emitted by all people and objects and, like radio waves, pass through opaque material. The T-wave machines “close their eyes” to anatomical details, providing some reassurance to privacy campaigners who fear people will be “stripped naked” by the machines.

Many of the 400 security staff at Canary Wharf have been trained in behaviour pattern recognition, based on a study of images of the body language of suicide bombers before they blow themselves up.

John Garwood, a spokesman for the Canary Wharf Group, which manages the 100-acre site where 80,000 people work and 100,000 visit each week, said the system was being installed to reassure companies, their staff and the public that the site was as safe as it could be. “This is not a response to a specific threat,” he said.

Patrick Mercer, the shadow homeland security minister, said: “Private industry is showing the government the way ahead with initiatives like this. One has to ask why something similar has yet to be done on the London Underground.”

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