Staff at UK airports are being allowed to work in highly sensitive areas such as passenger and baggage screening without security clearance.
Securicor ADI, which has security contracts at a number of airports including Heathrow, Gatwick and Manchester, admitted it allowed staff to work airside before they hadpassed a compulsory government counter-terrorist check (CTC).
But a Securicor ADI spokesman said this complied with government regulations. "Under these guide-lines, personnel can operate airside without having been CTC cleared, if they are working under the supervision of an individual who has passed through the DTLR's counter terrorism check," he said.
In the US, a federal task force has been appointed to oversee Securicor subsidiary Argenbright Holdings, the US's largest airport screening firm.
Argenbright has been accused by the government of potentially endangering the public. Securicor said all the alleged violations took place before it acquired the company.
But despite a number of security violations by airport security companies in the US, the US Senate's plans to make airport luggage and passenger screeners into federal employees are being resisted by the White House.
Meanwhile in Europe, airports face closure within days if they cannot bolster their war risk insurance when current temporary measures run out.
Airports, which used to be covered for up to $1bn (£691m) per incident, are now being offered a maximum of $50m (£34.6) per incident.
The European Commission has said there is little justification for reduced insurance cover at airports, as the risks had not increased in the same way as they have for airlines.
Airports are not included in the emergency insurance cover that governments were urged to arrange for airlines.
A spokesman for Airports Council International (ACI), representing around 450 European airports, said: "There have been no moves from the insurers and the governments. Cover runs out in less than two weeks so something has got to give."