Foreign criminals could be working air-side at Britain's airports because of a loophole in vetting requirements, it has emerged.

Since 2003 all staff who work in the "restricted zone" of terminals have had to undergo UK criminal records checks, but offences committed abroad are not covered.

This means that the estimated "thousands" of foreigners who work airside at British airports may not have been fully vetted.

The Department for Transport said checks of foreign criminal records are being considered as part of an independent review of personnel security announced in December.

More thorough "counter-terrorist checks" are required for staff who work in particularly sensitive areas.

Tory shadow home secretary David Davis said the loophole would be a "disgrace" if it proved to be a case of "commercial interest trumping public safety".

He called for immediate security checks to be carried out on all staff working airside, regardless of the cost.

Mr Davis told BBC Newsnight: "It's astonishing given the history, and of course the risk on the airside of any airport in the UK. To know about this for five years and do nothing about it is doubly astonishing.

"To not do anything about it because it's inconvenient when you think of the level of inconvenience they put passengers to... all no doubt for good reasons, but they're not going to put the companies through it."

He added: "They should immediately carry out security checks."