The recent fears focus on the understanding that Loganair staff undergo 'Basic Disclosure' checks – the lowest level of disclosure which only covers custodial sentences up to two and a half years and does not give information of any previous 'spent' convictions.

Our source, who does not want to be named, said: "It is not like an international airport where check-in staff only do check-in.

"Staff at smaller airports do all types of jobs, including being on the apron to load baggage and on the plane handing figures to the pilots, as well as dealing with firearms and sometimes escorting unaccompanied children."

They continued: "It would be really concerning if staff only had a basic disclosure certificate as this would not be a detailed background check.

"With all these responsibilities it would make sense that staff are required to have an enhanced disclosure certificate. It would be a disgrace if the only reason this does not happen is to save money."

When asked to confirm the level of disclosure and security checks that Loganair staff must go through prior to working, a spokesperson for the company said: "Beyond confirming that we fully comply with the requirements of the Department of Transport and the Airfield Operator in respect of security clearance for staff, we have no further comment to make publicly on security matters."

A spokesperson for the Department of Transport added: "Those working in airports undergo what is called a Standard CRC – criminal record check – although there are further requirements if a person works in a restricted zone.

"The level of checks depends on where someone works within the airport, but generally airports have two levels of security for those working in unrestricted zones and others working in restricted areas."