British border staff have confronted threats of arrest by Belgian police for making an attempt to cease individuals exploiting a loophole allowing them to enter the UK without passport checks, the BBC has learned. Passengers can travel from Brussels to Lille with out exhibiting passports as Belgium and France are each throughout the Schengen area, external. But they'll then stay on the train to the UK as there are no additional checks. The house Office confirmed it was working to sort out the "Lille loophole". The Schengen settlement, external allows passport-free journey between some European countries, however the UK will not be a signatory. Passengers with tickets from Brussels to Lille can board the prepare to London with out exhibiting a passport, however no-one checks whether passengers really get off the train at Lille and UK Border employees do not carry out checks on board. So passengers can continue on to London St Pancras, without going through further passport control, and illegally enter the nation. Radio 4's The Report, external has seen inner UK Border Agency, external (UKBA) correspondence highlighting the loophole, and the threats being made to employees attempting to deal with it. One UKBA officer describes an incident in April at a Brussels station the place he stopped two Iranians who he stated "bore all the hallmarks of Lille loopholers". After they were questioned the Belgian police intervened. The BBC has seen different emails describing clashes this 12 months between UK Border Agency staff and Belgian federal police. This led one officer to warn that many staff he had spoken to had been so fearful of being arrested by the Belgian police that they "will now flip a blind eye to potential Lille loopholers". The issue has been mentioned at the very best ranges of the UK Border Agency and the Foreign and Commonwealth Office, external. An electronic mail from a senior director to staff in May this yr acknowledged that the British Ambassador to Belgium had "voiced UKBA considerations on border controls for Lille passengers" to the Belgian immigration minister. The house Office, external minister Damian Green confirmed that each he and the home Secretary Theresa May are conscious of the loophole.