Thousands of foreigners working in high-security areas in Britain's airports do not undergo full criminal record checks.
Despite warnings that terrorists could recruit individuals with direct access to baggage and aircrafts, criminal record checks only apply to offences committed in the UK, rather than overseas.
This means that someone with convictions for firearms or explosives crimes overseas will not e detected by current checks.
The government have said that it would simply take too long and be too costly for authorities to do overseas criminal record checks.
Shadow Home Secretary David Davis said that the loopholes were "astonishing".
He told the BBC, who first broke the story: "To not do anything about it because it's inconvenient, it's a disgrace."
The government have undertaken a review of security in airports after WHSmith worker Samina Malik – dubbed the "lyrical terrorist" – was found to be in possesion of terrorist materials.
Around 200,000 people work for BAA air-side but the airport regulator would not confirm how many are foreign. However it is estimated to be in the thousands.
In a statement, the Department for Transport said: "Attempting to check overseas records would require the co-operation of a large number of foreign countries, delays and complex comparisons of international legal systems."
But a spokeswoman said the government was considering introducing checks on foreign criminal records as part of the transport review.
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