Channel 4's Dispatches has today received a list of landlords renting to around 300 MPs who are claiming this on expenses.
The total amount now claimed for MPs' rental expenses comes to more than a million pounds a year.
It is is the first time this list has been published and follows a battle with the parliamentary authorities following a Freedom of Information Request submitted by Dispatches which was stalled by an intervention by the House of Commons' Speaker John Bercow.
Channel 4 has just published the list on its website.
It reveals the name of an MP who has been letting their second home to another MP. Madeline Moon (Labour MP for Bridgend) is renting to Jessica Morden (Labour MP for Newport East).
The Freedom of Information request was made as a part of a Dispatches investigation looking into MPs expenses which is broadcast tonight at 8pm.
The programme will raise questions over the expenses of three ministers and a number of other senior MPs across all parties.