A minister was warned illegal immigrants were working for the police, guarding sensitive Whitehall buildings, eight months before the scandal was made public.
Immigration Minister Liam Byrne did not tell the Home Secretary for three months, it emerged yesterday.
Yet Home Office officials had been aware of the problem for more than two years.
Now as many as 10,000 illegal immigrants are estimated to have been cleared to work in the security industry.
But it has emerged that fewer than 400 have been stripped of the right to work.
In April, Mr Byrne was told illegal immigrants were working for the Metropolitan Police.
But he did not inform the then Home Secretary John Reid, whose successor Jacqui Smith was finally informed three months later.
Pressed to explain yesterday, Mr Byrne told MPs on the Home Affairs Committee: "If there was a big public announcement back when we were just beginning to understand the nature of the problem that may have undermined enforcement operations."
That doesn't, of course, explain why he didn't bother to tell his boss what was going on for fully three months. And, since just 4% of illegal immigrants given the right to work in the security industry have had that right revoked, I have to ask, "what enforcement operations?". No, the only operation that has gone on here was a cover-up operation. And even that was managed with typical Labour incompetence.