Home Secretary Theresa May has admitted she does not know how many people came into the UK without proper checks.
An inquiry has been ordered into claims identity checks on travellers from outside Europe were scaled back in the summer, without ministerial approval.
In a statement to MPs, Mrs May said those responsible would be punished. Brodie Clark, head of the UK border force, is among three staff suspended.
Labour accused Mrs May of giving "the green light for weaker controls".
No 10 has said Mrs May has the "full confidence" of the PM.
Mrs May told the Commons that while ministers had started a pilot project "targeting intelligence-led checks on higher-risk" passengers, Mr Clark had "authorised the wider relaxation of border controls without ministerial sanction".
She said: "As a result of these unauthorised actions, we will never know how many people entered the country who should have been prevented from doing so after being flagged by the warnings index."
What a frankly ridiculous situation this is.
http://www.bbc.co.uk/news/uk-politics-15615537