An illegal immigrant was able to work at the House of Commons using a fake identity pass in a serious breach of security.
The Government stands accused of a cover-up after leaked documents, obtained by The Sunday Telegraph, showed that Liam Byrne, the immigration minister, was informed immediately of the case of the Brazilian woman, a cleaner, when she was arrested at Parliament 10 days ago. Yet the Home Office confirmed the security breach - one of the most serious to affect Westminster - only after being contacted by this newspaper last night.
Elaine Chaves Aparecida was detained by police after a random check on her security pass showed that it belonged to someone else. She had been working there, since December 3 last year as the employee of a cleaning company, Emprise Services.
Under questioning, Miss Chaves, 31, admitted that she had run away from immigration officials at Heathrow Terminal 4 in December 2004 before she could be refused entry.
The letter from Tony Smith, the regional director of the immigration agency, admits that officials still have no idea how the Brazilian came to obtain a Commons pass or even to whom it belonged.
But, crucially, it predicts that the level of controversy will be "high" and advises ministers that they should take a "reactive approach" to the scandal.
It must be said that Mr Smith's warning was somewhat unnecessary. Advising this government (and particularly the Home Office, and especially Liam Byrne) to carry out a cover-up operation is, I think, akin to advising Derek Conway to stop being so selfless and consider his own interests once in a while.
As for Miss Chaves: I'd be particularly interested to know precisely what she meant when she "admitted that she had run away from immigration officials". Did she literally outrun them? Did she point behind them, say "look over there", and make her getaway while their backs were turned? Did she evade capture in some other, more subtle, manner? Whatever it was, it doesn't reflect very well on the immigration service. But then again, what does?