A senior minister, who is in charge of British security, was forced to apologise on Sunday for using public money to pay for adult films, an embarrassment for Prime Minister Gordon Brown as he prepares to host a G20 summit.

In the latest in a series of political rows over lawmakers' expenses, Home Secretary Jacqui Smith, already under investigation over her housing allowance, said she mistakenly claimed for pay-per-view television when she submitted a bill for her Internet connection.

Smith, whose large department oversees the police, counter-terrorism and immigration, will not resign and is focused on protecting G20 leaders meeting next week in London for talks on the financial crisis, a source close to her said.

The adult films, which costs five pounds each, were watched by Smith's husband, Richard Timney, while she was away from the family house in Worcester, central England, last April.

"They were adult films, that's all you need to know. Most people can use their imagination on that," the source told Reuters. "To say that she is angry with husband doesn't even come close to it."

A separate government ethics watchdog said last Monday it would review the allowances paid to members of parliament after a series of claims triggered public anger.

A poll on Sunday showed him 10 points behind the opposition Conservatives before an election due by June 2010.

Brown's spokesman offered support for Smith, saying in a statement that she had "done the right thing" in paying back the money as soon as she found out.

"She is doing a great job as Home Secretary and will not let this issue detract from her determination to ensure we protect the public and make our neighbourhoods safer," it said.

Smith said in a statement, "I am sorry that in claiming for my Internet connection, I mistakenly claimed for a television package alongside it."

Her husband said he was sorry for the embarrassment he had caused his wife.

"I can fully understand why people might be angry and offended by this," he told reporters outside his house. "Quite obviously a claim should never have been made for these films."

Parliament's sleaze watchdog is already looking into Smith's claims for 116,000 pounds to pay for accommodation in London when she was staying with her sister. Smith says she followed parliament's rules and has done nothing wrong.