A simple glance at the main Olympic Park in East London confirms this will be the most security-conscious Games in history: More than 11 miles of razor-wire-topped electric fencing separates the site from its surroundings, every entrance is guarded by soldiers and the surrounding streets and shopping malls are patrolled by police carrying 9mm semi-automatic weapons – an unusual sight in Britain, where armed patrols are normally found only at airports.

On the busiest days, 12,500 police officers will be on duty while 12,200 soldiers will carry out the venue security searches assisted by at least 7,000 contracted civilian security workers. A further 5,500 troops will be involved in military operations outside the site.

Visit NBCNews.com for breaking news, world news, and news about the economy

Every vehicle entering the site is scanned and searched, inside and out, by military teams in ‘sterile’ zones away from key buildings. The maximum-security athletes’ village is ringed by even more metal fences. It’s enough to prompt some to compare the Olympic Park to a prison.

But it’s the less obvious measures that have brought the greatest controversy to the Games. At least 1,850 closed-circuit television (CCTV) cameras feed pictures back across London to the joint police and government control center (NOCC) at New Scotland Yard, the headquarters of the city’s Metropolitan Police, according to a data access request by civil liberties campaign group, Big Brother Watch. (Olympic organizers refused to say on Tuesday how many cameras are in use.)

Visit NBCNews.com for breaking news, world news, and news about the economy

From NBC.