London: Military equipment, not seen in London since World War II, is being deployed to ensure security for the Olympics, setting aside opposition from some residents and preparing for what is officially called a "terrorist threat environment".
With the London Olympics set to begin on July 27, 3,500 Army personnel are being deployed on the ground while the Royal Air Force has positioned Rapier and High-velocity missiles.
The amphibious assault ship HMS Ocean berths at Greenwich today evening.
HMS Ocean is designed to deliver Royal Marines commandos to the centre of the action by helicopter or by landing craft - there are six helicopter operating spots on the flight deck, and the hangar can hold many more aircraft.
A Home Office spokesman said: "We are planning on a terrorist threat environment that is severe... We are not suggesting that there is any particular threat or risk to the Games that we know about".
Air Vice-Marshal Stuart Atha said at RAF Northolt today that "lethal force" will be used if the Olympics were threatened, and a plane will be shot down as a last resort in a "worst-case scenario".
Home Secretary Theresa May and Defence secretary Philip Hammond have assured there will be no compromise on Olympics security.
The total number of military personnel contributing to Olympics security is nearly 17,000.
A series of airspace restrictions around London and south-east England come into force from midnight tonight, lasting a month.
The prohibited zone will be about 30 miles wide and does not affect commercial aircraft, which fly in established air traffic corridors.
According to details released on how the Typhoons and Sea Kings would act if they intercepted an aircraft, a suspicious aircraft would be ordered to rock its wings, follow the military aircraft and turn away from London.
Flares and lasers could be fired by the military aircraft and, as a last resort, if an aircraft failed to comply with the directions of the military aircraft, it may be considered to be a threat to security, which may result in the use of lethal force.