The government has ordered an inquiry into security at London's Olympic park after a worker reportedly smuggled a fake bomb onto the site.
The man, who has been employed at the site for several years, allegedly carried an artificial bomb in the cabin of his digger through two checkpoints without being searched by security staff.
The Home Office said it had asked Locog, the organiser of the Games, to look into the incident and report back to the home secretary.
According to the Sun on Sunday the worker 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.
He told the paper he had become concerned after noticing he was only searched by security when he entered the site in the mornings, and that he could enter and exit the grounds in his digger during the day without further checks.
"I can meet anyone on the outside without anyone knowing and bring anything inside without anyone checking. If I had terrorist connections I could be bringing in explosives, chemicals – anything at all. It's a massive security loophole."
He added that 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.
Locog insisted the site would be searched and locked down before the Games begin in less than three months time.
A spokeswoman said: "As you would expect our security increases significantly the closer we get to the Games. The park and the village will be searched and sealed before it is locked down for Games time."
The bill for security at the Olympics is set to top £1bn and includes 23,700 guards bolstered by up to 13,500 troops at peak times.
The RAF will be on standby and batteries of surface-to-air missiles are being considered at up to six sites to deter an airborne attacks. Last month, the Ministry of Defence announced that military snipers deployed in helicopters would also be patrolling the skies during the event and, if required, would shoot pilots of low-flying aircraft that might be involved in terrorist attacks.
On Saturday, all 40,000 fans who attended the official opening had to go through full airport-style security and some were also searched in marquees. Armed guards patrolled the site, which has been surrounded by an 11-mile electric fence, at a cost £80m.
The Locog spokeswoman added; "Clearly a tupperware box containing batteries, a moblie phone and some loose wires would not pose a security threat on a construction site. However, we will be looking into the allegations to ensure our security regimes are as robust as they need to be at this time."
