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
After the heatwave come the storms, with lightning flashes illuminating the night sky across much of the country last night.
An Independence Day event at a UK base has been cancelled by the US Air Force over security fears.
British firms predict the economy should sustain a "solid" pace of growth for the rest of the year thanks to lower oil prices and inflation.