A senior UK Border Agency official authorised the relaxation of border controls without ministerial sanction, Home Secretary Theresa May has told the House of Commons.
Mrs May said that while ministers had started a pilot project "targeting intelligence-led checks on higher-risk" passengers, the head of the UK Border Agency Brodie Clark had "authorised the wider relaxation of border controls without ministerial sanction".
She admitted it would never be known how many people had entered the country without proper checks, and said that those responsible for going beyond the scope of the pilot programme must be punished. Mr Clark is among three staff currently suspended as a result of the allegations.
In a statement to the Commons on 7 November 2011, the home secretary announced she had launched three inquiries into claims that identity checks on travellers from outside Europe were scaled back in the summer without ministerial approval.
Responding to Mrs May's statement shadow home office minister Yvette Cooper accused the home secretary of giving "the green light" to "weaker controls" in order to cut queues at passport control.
Ministers, not officials, were to blame, she argued, telling Mrs May to "get a grip and stop passing the buck".
Ms Cooper also called for the investigations to cover the resource pressures facing UKBA which, she said, was losing 6,500 staff, including 1,500 from the UK Border Force.
Former Labour Home Secretary Jack Straw demanded to know why ministers did not realise that their instructions on passport checks were not being followed by UKBA officials.
Conservative backbencher Anne Main blamed the previous Labour government, alleging it was responsible for encouraging laxity among border staff.