Culture Secretary Maria Miller is to have her expenses investigated by the Parliamentary sleaze watchdog, it was announced today.
The office of John Lyon, the Parliamentary Commissioner for Standards, said he was opening an inquiry following a complaint that Mrs Miller had claimed more than £90,000 in second home allowances towards the cost of a house where her parents lived.
The complaint was lodged earlier this week by Labour MP John Mann, who claimed the arrangement was "identical" to that of former Labour minister Tony McNulty, who in 2009 was required to pay back more than £13,000 in expenses claimed on a second home occupied by his parents.
In that case, the Commissioner said McNulty had effectively "subsidised" his parents from the public purse by allowing them to live rent free.
Earlier this week Miller insisted that all of her expenses were "absolutely as they should be".
A spokesman for Miller said: "Mrs Miller's expenses have been audited twice and found to be wholly proper and above board.
"Any suggestion to the contrary is simply untrue.
"She would fully co-operate with any inquiry."
Asked earlier today at a regular Westminster briefing if Prime Minister David Cameron had full confidence in the Culture Secretary, a Downing Street spokeswoman said: "Yes, indeed he does."
Questions about Miller's expenses have drawn the Culture Secretary into a further row about her office's dealings with the Daily Telegraph, whose investigation led to the commissioner's inquiry.
An aide to Miller was reported to have called the newspaper and said she wanted to "flag up" the Cabinet minister's connection to press regulation during discussions about a story on the Culture Secretary's expenses.
Downing Street's top spin doctor, Craig Oliver, also mentioned the Leveson press reforms in a telephone call to the Telegraph's editor.
No 10 insisted yesterday that Oliver was highlighting concerns about the way the Telegraph carried out its investigation into Mrs Miller's expenses claims, rather than attempting to threaten the newspaper.
The director of communications reportedly told editor Tony Gallagher "she (Maria Miller) is looking at Leveson at the moment" during the call last Friday.
Miller claimed second home allowances of £90,718 - almost the maximum permitted - between 2005 and 2009 towards mortgage payments, bills and other costs relating to a house where her parents had apparently been living since 1996.
In an interview with the Evening Standard, Mrs Miller said one of the two audits had been carried out by former civil servant Sir Thomas Legg - who was called in to review all MPs' claims at the height of the expenses scandal - and the other by the Conservative Party.
Asked whether Sir Thomas was aware that her parents were living at her designated second home, Miller said: "I obviously spoke to the Fees Office about my claims and they were happy that everything was in order."
She also denied that she had used her position overseeing the post-Leveson reforms of press regulation to ward off the Telegraph.
"This has nothing to do with the Leveson inquiry. My concern is that any investigation is done in accordance with the rules, the Editors' Code," she said.
"What I did was to contact the editor of the Telegraph directly to express my concern at the way his investigation was being undertaken."
She added: "The journalist hadn't contacted my office first. She had doorstepped a member of my family, a person who is not in public life, a person ill-equipped to deal with national media inquiries on my behalf."
Her special adviser, Joanna Hindley, reportedly told Telegraph reporters investigating her expenses: "Maria has obviously been having quite a lot of editors' meetings around Leveson at the moment. I am just going to flag up that connection for you to think about."