Jacqui Smith’s future in the Cabinet was in doubt last night after her husband claimed the cost of two pornographic films from her parliamentary expenses budget.

The Home Secretary, who is already under investigation over her housing arrangements, was “mortified and furious” after it emerged that her expenses claims included two 18-rated films, each costing £5, viewed on April 1 and April 6 last year.

The Times has learnt that MPs are expected to call in the police today over how a copy of an invoice from her Virgin TV and internet account, submitted to the Commons as part of an expenses claim, came to be published in a Sunday newspaper.

Some MPs believe that digital images of all MPs’ invoices, which have been scanned for release later this year, may have been stolen and are being offered to newspapers for money. The suggestion will cause anger and fear among MPs, who have been campaigning against the release of this information.

However the invoice emerged, it is unlikely to take the pressure off Ms Smith, whose husband, Richard Timney, was sent out by his wife to make a public statement yesterday.

Speaking to reporters outside their constituency home in Redditch, Worcestershire, he said: “I am really sorry for any embarrassment I have caused Jacqui. I can fully understand why people might be angry and offended by this. Quite obviously, a claim should never have been made for these films and, as you know, the money has been paid back.”

Whitehall sources indicated that they were unimpressed with the way he handled the statement, which included no apology to the taxpayer.

Mr Timney, who lives in Redditch with their two sons aged 15 and 10, is employed at public expense as a parliamentary assistant to his wife. He is likely to have filled in the claim form for the £67 Virgin Media bill, although his wife would have had to sign for it.

The bill also included two viewings of the film Ocean’s 13, at £3.75 each, and £3.50 to watch the children’s film Surf’s Up.

Ms Smith’s career is now in the balance amid growing suspicion that she will be moved or even demoted in a reshuffle immediately before or after the summer break. Mr Brown is unlikely to take action this week, on the eve of the G20 summit. Downing Street said yesterday that it had been an “inadvertent mistake” and she was doing a “great job” as Home Secretary.

Ms Smith said: “I am sorry that, in claiming for my internet connection, I mistakenly claimed for a television package alongside it. As soon as the matter was brought to my attention, I took steps to contact the relevant parliamentary authorities and rectify the situation. All money claimed for the television package will be paid back in full.”

Ms Smith is already being investigated by John Lyon, the Parliamentary Commissioner for Standards, over her decision to designate her sister’s house in London as her “main home”. This allowed her to claim £116,000 on her Redditch constituency house, where her family live, as her “second home”. Mr Lyon accepted a complaint about Ms Smith’s claims and has called on her to explain the £116,000 that she has claimed since becoming an MP.

David Davis, the former Shadow Home Secretary, said: “I didn’t even know films were that expensive . . . claiming for films? I can’t believe it.”

Last week the Committee on Standards in Public Life announced that it would be carrying out a review of the whole system, but that it did not plan to report on the matter until after the next general election.

Money Central: MPs' 10 most outrageous expense claims ever

Times Recommends

• Baroness Ashton: EU couldn’t make it up
• The other belles de nos jours
• Why too much of a good thing is bad for you