The Independent Parliamentary Standards Authority (Ipsa) has announced 70 politicians have agreed to repay profits from taxpayer-funded homes.
The sums range from a few hundred pounds in some cases to the £81,446 paid by the Welsh Secretary David Jones and the £61,403 returned by DUP East Londonderry MP Gregory Campbell - both for properties in London.
Conservative MP Stewart Jackson has said he is resisting legal action from Ipsa to recover the sums it says he owes, and is mounting his own legal challenge to the watchdog's claim his family home increased in value by 20% at a time when he says house prices in the area were falling.
"Ipsa's legal proceedings are heavy-handed and disproportionate and are clearly intended to bully me into submission.
"The essence of the dispute is my challenge of the valuations of 2010 and 2012.
"Ipsa are seeking a cash sum on a so-called capital gain 'profit' on my family home, in which I live and have not sold.
"The money which Ipsa is demanding retrospectively is more than the total amount I received when I was claiming mortgage interest and the property is now valued at less than we purchased it for in 2005.
"At my own expense, I have paid for an accurate recent expert valuation and I have made a reasonable offer to Ipsa to settle the matter and reduce the legal costs which will have to be met by the taxpayer."
Peterborough MP Stewart Jackson is being sued by the parliamentary watchdog for not paying back £54,000, which they say he owes. Now the IPSA has issued High Court proceedings.
It calculated that Mr Jackson owes the capital gains on his 2nd home between 2010 and 2012. In a statement, the MP says the legal proceedings are heavy handed and disproportionate and that the property is now worth less than when he bought it.
The identities of 51 MPs' landlords have been kept secret on security grounds.
The expenses watchdog 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.
The Independent Parliamentary Standards Authority (Ipsa) did not include 51 of the 320 MPs who claim rental expenses after complaints that publishing their landlord's names would present a security risk.
Details had been removed where an MP or landlord had shown the information that could lead to their address being identified.