The political storm over relaxed border controls at UK ports during the peak summer period is set to continue as Home Secretary Theresa May faces another grilling by MPs.
On Monday, Mrs May admitted authorising a watering down of checks on Britons and other EU nationals. But senior officials at the UK's border force went further, scrapping key checks against a Home Office database without ministerial approval, she said in a statement.
The number of suspected terrorists, criminals and illegal immigrants who entered the country as a result of the move will never be known, Mrs May said.
Three staff, including the head of the UK border force Brodie Clark, have been suspended and those responsible will be punished "to make sure that border force officials can never take such risks with border security again", she said.
Labour accuses her of giving the "green light" to the policy and she will be pressed further for details of how it unfolded when she appears before the Home Affairs Select Committee. Its Labour chairman, former minister Keith Vaz, has complained of a "culture of complacency" and suggested the Home Secretary's office must have been informed of the policy.
Mr Clark confirmed he had gone further than the pilot scheme allowed when John Vine, the independent chief inspector of the UK Border Agency (UKBA), raised concerns last week, Mrs May told the Commons.
Biometric checks on European nationals and checks against the Home Office database on children from the European Economic Area (EEA) "were abandoned on a regular basis, without ministerial approval", she said. Adults were not checked against the database at Calais and the fingerprints of non-European nationals from countries that require a visa were stopped.
"I did not give my consent or authorisation for any of these decisions," Mrs May insisted. "Indeed I told officials explicitly that the pilot was to go no further than we had agreed."
The Public and Commercial Services union has claimed that border controls were relaxed to keep queues down despite cuts to personnel.
Some 5,200 staff will be cut from the UKBA, taking its numbers down to 18,000, by 2015, with 1,552 jobs to go in the UK border force before the next general election, including 886 this financial year, MPs heard. But Mrs May denied the cuts led to the unauthorised reductions in border controls.