More than 50 MPs have been allowed to keep the name of their landlord secret on security grounds.
The expenses watchdog has published a list of landlords who are paid taxpayer-funded rent by MPs after a freedom of information request. The release showed that a number of MPs rent their properties to fellow MPs or peers.
However, the Independent Parliamentary Standards Authority (Ipsa) did not include 51 of the 320 MPs who claim rental expenses after complaints that to publish their landlord's name would present a security risk.
Details had been removed where an MP or landlord had shown the information could lead to their address being identified.
An Ipsa spokesman said 85% of MPs had their landlords named, but added: "We need to consider in each case whether there are any security issues. We take that as seriously as we can."
The move follows a row with MPs, who argued in the Commons last month that the information could be used maliciously.
Commons Speaker John Bercow wrote to Ipsa claiming there was a "very real danger" that residential addresses could be discovered as a result of the details being released.
Yesterday's publication showed a number of MPs rent their properties from fellow MPs or peers.
Labour MP Jessica Morden (Newport East) rents from Madeleine Moon (Bridgend) while Conservative Keith Simpson rents from Lord Flight.
The Sun newspaper also claimed that Tory MP Peter Luff (Mid Worcestershire) rents a London flat from Chelsea footballer Frank Lampard using taxpayers' money, while letting out his own London home.
A spokesman for Lampard told the paper said the star did not know who the management company let the property to, while a representative for Mr Luff added the MP had no idea whether he was renting from Lampard or not.
Equalities Minister Helen Grant has also defended her claim for the maximum in expenses to cover accommodation in London despite living just 19 miles from the Commons.
Mrs Grant lives in a £1.8 million home in Reigate, Surrey - outside her Maidstone constituency - and also rents a Thameside flat near the MI6 building in Vauxhall, funded by the taxpayer.
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The Conservative minister is eligible for a second home allowance on parliamentary expenses because her constituency is outside London.
The expense claims were uncovered in an investigation by Channel 4's Dispatches.
A spokeswoman for Mrs Grant said: "Mrs Grant's constituency has been deemed by Ipsa to be a non-London constituency and she is therefore fully entitled to use her rental accommodation allowance either in London or in the constituency.
"She has a base in her constituency at her mother's property, where her son also lives, so she sees no need to rent a further property there.
"The focus of her time and responsibility has always been Maidstone and the Weald."
Mrs Grant's London flat is supported by expense claims of £1,666.67 per month - the maximum allowed within the rules, which caps rental claims at £20,000 per year. Mrs Grant has filed claims for rent since March this year.
