Attorney General Baroness Scotland felt betrayed when she realised her housemaid told "barefaced lies" to get the job, a court heard today.
Loloahi Tapui told her she knew who she was and understood why it was important everything was done correctly when she applied for a job as her cleaner in September last year, Baroness Scotland, the chief law officer for England, Wales and Northern Ireland, said.
But Tapui, 27, had lied and overstayed her visa by four years, Southwark Crown Court in London heard.
Today, Baroness Scotland denied she had been so busy with her work she simply assumed Tapui had the right to remain and work in the UK because her husband Alex Zivancevic was a lawyer and spoke with an English accent.
"That's not true," she said.
Under cross examination by Christopher Hehir, defending Tapui, she insisted all of Tapui's documents had been checked but admitted she had made a mistake by not taking copies of them.
"I made a mistake for which I am very sorry," she said.
"I'm so sorry about this. I can't tell you how sorry I am.
"But I'm afraid it still doesn't change the fact that she asserted she was lawfully entitled to be in this country and lawfully available for work. She was not. She lied to me."
Baroness Scotland told the jury the passport she saw was different to the one produced in court - which expired before Tapui started working for her - and added she would have checked the documents as she was always careful who she let work in her home.
"I thought this woman was married to a member of the legal profession," she said.
"It never crossed my mind that a lawyer in this country would be married to an illegal immigrant and then pass her off as a cleaner to the Attorney General.
"You would need to be brain dead to do something like that."
The jury of eight men and four women heard Baroness Scotland was fined £5,000 for failing to keep copies of documents which purported to show Tapui's entitlement to work in the UK under a law which she had helped to bring into force while a junior minister at the Home Office.
Baroness Scotland - who asked to be referred to by her married name of Patricia Mawhinney - said: "It's something I bitterly regret now. Frankly, I believed her."
With her voice faltering, she added: "I'd had a pretty tough couple of months, a number of bereavements in my family. It came at a difficult time."
The court heard her mother died on December 9 last year, followed by her brother on December 19. His funeral took place on January 15, just one week before she interviewed Tapui for the cleaner's job.
Wearing a brown paisley floral dress as she gave evidence, Baroness Scotland, who described herself as a "committed Catholic", told the jury she stressed how important honesty and following the rules were to her during the interview on January 23, 2009.
Baroness Scotland told the jury: "She said, 'Don't worry, we understand your need for security and your need to do everything correctly."'
Asked if the case had caused her any political embarrassment, Baroness Scotland said: "It's caused me considerable pain, but it's caused my family more.
"What she has done has been quite extraordinary. To have lied as she has lied and to damage someone who has tried to be kind to you is quite a difficult thing to accept.
"I was actually really hurt and did ask her how she could do this to me and that's when she said she was sorry."
Shaking her head, she added: "She wasn't so sorry she didn't do it."
The Attorney General said when she first confronted Tapui about the allegations, Tapui told her she had never produced her passport, saying she had not left the UK for two years and had lost it.
"She said, 'I lied to you, Patricia, I lied to you."'
Baroness Scotland said when she asked why, she said: "Because I wanted the job and I knew you wouldn't give me the job if you knew that was my position."
Baroness Scotland went on: "I couldn't believe what Loloahi was saying. She was suggesting she hadn't even produced a passport and that she hadn't produced a document.
"This was another barefaced lie she had told me to get the job."
The court heard Tapui consulted an immigration lawyer in 2004 when she had an application to remain in the UK pending with the Home Office, but had never followed it up.
But Baroness Scotland said she was not aware of this until after the allegations emerged.
"Whatever the situation was, I couldn't trust her any more," she said.
She said she was unable to contact Tapui over the phone so sent her a text saying she was dismissed from her job, for which she was being paid £6.50 per hour.
Tapui, of Sutton Court Road, Chiswick, west London, admits possessing a passport with a counterfeit visa stamp between June 7 2006 and September 19 2009, but denies using it to establish facts about herself and earn money.
In police interview, Tapui said she had got the fake stamp off an unnamed friend of a former Russian housemate called Alex, whom she had paid £180 in cash.
She also denies fraud by dishonestly making a false representation that she was entitled to work in the UK.
Judge Nicholas Loraine-Smith adjourned the trial, expected to last three to four days, to tomorrow, warning the jury to try the case on the evidence before them and to ignore any press reports.