The Tory MP said she was told she was keeping within the rules
An MP whose daughter lived rent free in a taxpayer-funded flat has been told to repay £7,100 and apologise in writing.
Anne Main began claiming expenses on a rented flat in St Albans shortly after becoming its MP in 2005, even though her family home was only 20 miles away.
The standards watchdog approved this arrangement but said her daughter's living costs should not have been subsidised out of the public purse.
Mrs Main said the authorities advised her she was acting within the rules.
The Conservative MP survived an attempt to deselect her as a candidate last year following publicity over her expenses, leading her to say she had the "overwhelming" support of members to stand in the upcoming election.
In his investigation into the MP's claims, Standards Commissioner John Lyon ruled that it was fair for her to designate her family home in Beaconsfield as her main residence for expenses purposes, and to treat the flat, where she spent one or two nights a week, as her second home.
But he said her adult daughter, who is employed, spent more time at the flat than the MP did, living there rent-free and paying no household bills.
Mr Lyon said the MP told him that the Parliamentary authorities advised her it was within the rules for her children to share her second home, and that her daughter's use of the property added nothing to the cost of buying, maintaining or heating it.
But Mr Lyon concluded that public funds should not have been "expected" to meet her living costs while she was resident there.
"That should have been a private matter for the family," he concluded.
The watchdog also found that Mrs Main breached Commons rules by claiming more than £3,000 a year between 2005 and 2008 for food consumed while she was away from her main home.
The rules state that MPs whose main homes are neither in London nor their constituency could claim for food while at Westminster or at their constituency, but not both.
The Commons Standards and Privileges Committee, which has the power to impose sanctions on MPs, accepted the watchdog's findings and told Mrs Main to repay £5,000 in respect of her daughter's estimated living costs over the period.
The MP will also have to pay £2,100 wrongly claimed for food.
The report was published on the same day as Sir Thomas Legg's review of all MPs' expenses claims over the past five years.
Sir Thomas told Mrs Main to repay £1,388.59 relating to overpayments for rent and service charges but noted that she had already repaid £1,788.49 since last April.
Several MPs from all parties have already apologised and repaid money after formal investigations into their expenses.
In the first case of its kind, MPs voted earlier this week to withhold the resettlement grant paid to retiring MPs from Labour's Harry Cohen.
This came after the Parliamentary Standards Commissioner found he had committed a "particularly serious" breach of the rules over his second homes allowance.