Paul Hackett / Reuters

Spectators find their seats at the official opening of the London Olympics stadium, inside the Olympic park, London, Saturday.

Britain has begun an inquiry into security at the London Olympics after a worker reportedly smuggled a fake bomb onto the site to expose flaws in its anti-terror defenses.

The worker carried the artificial bomb through two checkpoints without being searched by security staff, according to a British tabloid newspaper report.

Once inside, he was able to drive the package through the site, taking it past the velodrome before posing for a photograph with it outside the Olympic Stadium, The Sun reported.

The stunt, 24 hours before 40,000 people attended the official opening of the stadium on Saturday, was designed to show how vulnerable the site, which also includes the athletes' village, could be to a terrorist attack.

Fears that the international spectacle could be targeted by extremists have led organisers to spend $1.6 billion (£1 billion) on security for the games including 23,700 guards, 14,000 troops at key times and an 11-mile electric fence.

A spokesman for Britain’s Home Office told The Telegraph it had asked games organizers to "look into this incident and report back to the Home Secretary urgently".

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