The head of the UK Border Force has been suspended amid claims that passport checks for non-EU nationals were quietly dropped this summer.
Brodie Clark is one of three senior officials thought to have been suspended while an investigation into the allegations is conducted.
The Home Office refused to comment on a report that guards at the Border Force - part of the UK Border Agency - had been told not to bother with certain passport checks.
But a spokesman said: "Head of UKBA Border Force Brodie Clark has been suspended."
Confirmation of Mr Clark's suspension came after the Daily Mail reported that border checks had been relaxed earlier this year without the knowledge of ministers.
According to the paper, border guards were told not to bother checking biometric chips on the passports of citizens from outside the EU to ensure they are not fraudsters.
The guards were also instructed not to bother checking fingerprints and other personal details against a Home Office database of terror suspects and illegal immigrants, it said.
The chairman of the Home Affairs Select Committee described the suspensions as "extraordinary" and said he would be questioning Home Secretary Theresa May about the issue on Tuesday.
Keith Vaz, a Labour MP, said: "These developments are extraordinary in that they involve such senior members of the UK Border Agency. Only a day after the publication of our report which concluded that the Border Agency continues to fail we have this remarkable news.
"We will question the Home Secretary about this on Tuesday when she comes before the committee. If her answers do not satisfy us I am sure the committee will want to conduct its own inquiry. The Border Police are supposed to keep people out, not let people in."
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