A BBC investigation into the finances of Northern Ireland politicians Iris Robinson and her husband reportedly prompted her to reveal details of her affair and attempted suicide.

According to The Times, an “embarrassing” television documentary was to be broadcast with allegations over the first family’s financial affairs.

Investigative journalist Darragh McIntyre appeared at Stormont accompanied with a camera crew on Tuesday to ask Mr Robinson, Northern Ireland’s first minister, a series of questions.

Yesterday afternoon, Mrs Robinson released a statement admitting to the affair and suicide attempt. She announced last month she was leaving politics due to ill mental health.

The affair was thought to have happened around the same time she made a series of homophobic comments in the media in the summer of 2008.

In the statement, she did not name her lover but said she had “encouraged friends to assist him by providing financial support for a business venture”.

Mr Robinson was asked by the BBC if he and his wife had done anything illegal.

Without mentioning his wife, he said: “I am absolutely certain that everything I have done has been done as it should.

“Yesterday I received a letter from an organisation within the BBC. It contained no allegation against me. The BBC asked questions that can be easily answered but there are no allegations that will stand.”

The BBC said its Spotlight programme had been investigating matters involving Mrs Robinson for some time.

The couple were exposed in the expenses scandal for claiming almost £600,000 a year in salaries and expenses.

They earned six salaries between them and employed four family members as staff.

She earned £63,291 for her position as an MP, £24,296 as an Assembly member and as chairwoman of its health and social services committee and £9,550 as a councillor for the Castlereagh borough in Northern Ireland.

Her husband was found to earn £63,291 as MP for East Belfast, £71,434 for his role as first minister plus a third of the £43,101 salary for being an Assembly member because he is also an MP.