Security for the 2012 Summer Olympics Security for the 2012 Summer Olympics was provided by several arms of the British Armed Forces . The security operation was led by the police , with 13 , 000 officers available , supported by 17 , 000 members of the armed forces . Naval and air assets , including ships situated in the Thames , Eurofighter jets and surface - to - air missiles , which were deployed as part of the security operation . The final cost of the security operation was estimated 553m pounds sterling . The budget for venue security was being partly funded by LOCOG as well as using the contingency from the £9 . 3 billion infrastructure budget . Private security firm G4S , after scandals regarding training and manpower emerged mere weeks before the games did not provide their planned 13 , 700 staff ; the number was instead approximately 10 , 000 . This was be the biggest security operation Britain had faced for decades as the number of security personnel totalled 40 , 000 . The day after the city was selected to host the Olympics , the London Underground and a London Bus was attacked by Al - Qaeda terrorist . Air defences . Air defences were installed around the Olympic stadium to stop potential suicide airplane attacks , similar to the 9 / 11 terrorist attacks in the USA . There were six missile sites , four using Rapier missile s and two using Starstreak missile s . After initially announcing the possibility of installing missiles the British government confirmed they would be deployed from mid July . Rapier missiles are surface - to - air missiles designed to shoot down aeroplanes . A short - range air defence system , it consists of eight missiles with a tracking radar and a surveillance radar . There were four rapier sites - two in north London and two in south London . The rapier sites were : In addition two sites were selected for Starstreak missiles . They were at the top of tall buildings closer to the Olympic Stadium . One of the sites was the water tower of a factory converted into upmarket flats in Bow . The other was a 15 story block of Council flats in Leytonstone . The residents of the latter took the government to court to protest against the siting of the missile battery , a case they lost on 10 July 2012 . The starstreak sites were : The defences were tested in a large training exercise during 2 – 10 May 2012 , known as " Exercise Olympic Guardian " , which preceded the operational phase of the campaign . The exercise involved Boeing E - 3 Sentry from RAF Waddington , VC - 10 tanker aircraft from RAF Brize Norton and Typhoon fast jets from 3 ( F ) Sqn operating from RAF Northolt , the first time RAF fighters had been stationed at the West London base since the Second World War . Supporting the air defence role over London were RAF Puma s based at the TA Centre at Ilford , Fleet Air Arm Sea King s at Northolt , and Army Air Corps and four FAA Lynx es operating from HMS Ocean , which was moored on the Thames . Airborne early warning security were supplemented by Type 101 ground - based radar from 1 Air Control Centre , deployed to Kent , together with three - man Army teams positioned around London , equipped with binoculars . From 14 July 2012 , Royal Air Force , Army and Navy assets and personnel began enforcing a 30 - mile exclusion zone over London and other areas , though this is not expected to affect commercial on established routes . Maritime defences . The Royal Navy and Royal Marines were equipped with the Long Range Acoustic Device ( LRAD ) , which uses directional sound as an anti - personnel weapon . It was attached to a landing craft on the Thames at Westminster , and was to be used primarily in loud - hailer mode as a so - called acoustic hailing device , rather than as a weapon . Royal Marines operated from HMS Ocean in small craft armed with conventional weapons . IT Security . BT were responsible for the IT infrastructure for the Olympics , and for securing the network perimeter against electronic attacks . The company had been warned to expect a high intensity of complex and determined attacks , but instead found that the attacks were " unsophisticated and perpetrated by children " . When monitoring social media and chat sites for information on which targets might be attacked next , BT staff observed one would - be hacker breaking off a planning session because their mother was calling them to eat their tea , and another defending their technical performance by saying " what do you expect , I ’ m only 12 ? " . The other main IT security obstacle encountered was the requirement to allow over 25 , 000 journalists access to network services ; many of their computers were infected with viruses or other malware . BT contacted a number of spam blacklisting companies to explain the resulting increase in spam from its network . Preparation concerns . After it emerged in July 2012 that G4S , the company in charge of providing security , was unable to train enough security staff , an additional 3 , 500 soldiers , sailors , airmen and marines were assigned to security duties at the Olympics . Lord Coe , chairman of LOCOG , said that the security of the Olympics had not been compromised as a result .