Some of the people who spoke to ITV News about alleged security breaches by G4S staff were sacked by the G4S and have tribunal cases against the company.
The man in charge of the operation, the G4S Managing Director of Global Events, Ian Horseman Sewell, rejected all their claims:
"At no point is there any evidence that dogs that have been trained to detect substances other than explosives have been used to try to detect explosives."
More top news
iPhone users are being targeted by a new scam asking customers for their personal details.
The youngsters were found unharmed in a Toyota after it failed to stop on the M25.
Labour is facing the embarrassing prospect of coming third, behind the Conservatives, in the Scottish parliamentary elections.