Passport checks have been relaxed too often in recent years because of "highly troubling" mistakes by executives at the UK Border Agency, MPs warned.
In an attempt to rebuild its damaged reputation, they called for an overhaul of the way the agency deals with its political masters at the Home Office.
The Commons home affairs select committee reached its verdict after an inquiry into the secret relaxation of border controls that led to the resignation of Brodie Clark as the agency's head. He admitted regularly easing fingerprint checks, without permission from the Government, under rules designed for health and safety emergencies.
He fiercely denies the Home Office's accusation that he was a "rogue officer" and is suing Theresa May, the Home Secretary, for constructive dismissal, claiming she led a campaign to vilify him.
Yesterday, the committee painted a picture of a poorly-performing agency which had negligible supervision of senior staff and little contact with the Home Office. "Mr Clark was running the UK Border Force without effective checks or balances from either his superiors or immediate colleagues," the MPs' said. "The chain of communication from ministers, to senior management, to frontline staff of the UK Border Agency is a long and convoluted one, and it seems to have become seriously fragmented."
The MPs said they were "very concerned" about the over-use of five-year-old guidance permitting the suspension of checks of new arrivals against a watch-list of suspected terrorists when queues of passengers became too long.
They said were shocked by the sheer number of times the emergency rules were invoked, including almost 100 times at Calais alone.