Smith, the Home Secretary, can claim up to £24,000 a year for that house in Redditch, she shares with her husband and their two sons, because she has told the Commons her sister's £350,000 terraced home in south east London is her main residence.
She stays at her sister's Nunhead home when she is London - normally Monday to Thursday - as The-Latest reported last year when we disclosed that round the clock armed protection there costs almost £1m a year on top .
A spokeswoman for Smith said she had "fully abided" with expenses rules. The Mail on Sunday says Smith has claimed more than £116,000 in second home expenses - known as the Additional Costs Allowance - over several years.
The allowance is to help cover the cost of MPs having to have a second home - or place to stay - in London if their constituency is too far away to allow commuting to Parliament.
It can cover mortgage interest, fuel bills and things like a new kitchen, bathroom or even the purchase of items such as flat screen televisions and fridges.
The rules state that the main residence is where the MP "spends more nights than any other".
Under the rules, which have been in the spotlight over the past year over allegations of sleaze, Parliament leaves it up to MPs to decide whether their London or constituency home is their "second home".
A spokeswoman for Smith said: "The home secretary has always abided fully with Parliament's clear rules on expenses and has long-standing written approval from the Parliamentary Fees Office for any agreed expenses."
"She spends the majority of her time in London attending to government business and has full approval for any associated expenses relating to her second home in her West Midlands constituency."
The Mail on Sunday also says that Smith qualified as Home Secretary for a free "grace and favour" home in Whitehall - which if she took would mean she could not claim for a second home.
On her website Smith clearly states that she lives in her constituency.