London Telegraph 
May 6, 2012
The man, who has been employed at the site for several years, allegedly carried the artificial bomb in the cabin of his digger through two checkpoints without being searched by security staff.
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 on Sunday reported.
The stunt, 24 hours before 40,000 people attended the official opening of the stadium, 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 billion on security for the games including 23,700 guards, 14,000 troops at key times and an 11-mile electric fence which alone cost £80 million.