Six of Northern Ireland's Democratic Unionist MPs have been told to hand back almost £144,000 worth of profits from taxpayer-funded homes, it has been revealed.
The Independent Parliamentary Standards Authority (Ipsa) announced that 70 UK politicians have agreed to repay hundreds of thousands of pounds following negotiations.
The expenses watchdog moved to ban the use of Commons expenses to pay mortgage interest in May 2010, in the wake of public fury over "flipping" and other abuses.
However, transitional arrangements were put in place permitting MPs elected before 2010 to keep claiming the money up to last August - as long as they agreed to return any potential capital gain made from the rising value of London properties.
East Londonderry MP Gregory Campbell has agreed to return £61,403 for a property in London he still owns - the second-largest repayment to be made.
Gregory Campbell (DUP, East Londonderry)
Total mortgage interest claimed £16,755.00
Total repayment due to IPSA £61,403.18
David Simpson (DUP, Upper Bann)
Total mortgage interest claimed £11,208.65
Total repayment due to IPSA £30,308.40
William McCrea (DUP, South Antrim)
Total mortgage interest claimed £6,929.91
Total repayment due to IPSA £29,793.60
Nigel Dodds (DUP, Belfast North)
Total mortgage interest claimed £25,434.16
Total repayment due to IPSA £19,507.76
Jeffrey Donaldson (DUP, Lagan Valley)
Total mortgage interest claimed £20,338.06
Total repayment due to IPSA £1,448.46
Sammy Wilson (DUP, East Antrim)
Total mortgage interest claimed £19,633.90
Total repayment due to IPSA £1,448.46
Some 71 Members of Parliament received around £1 million in allowances for mortgage interest during the period.
The properties were formally valued at the beginning and the end, and the MPs were given until November 30 to return a proportion of any gain.
Ipsa said it would consider a longer repayment schedule - possibly extending to 2015 - if returning cash quickly would "create hardship".
But the process was delayed when a number of MPs signalled that they were considering a legal challenge on the grounds that the watchdog had overstepped its powers.
Repayment deals have now been struck with 70 of the MPs, with only Conservative MP Stewart Jackson's case still to be settled. He has been asked to hand over £54,000 in relation to a property in his Peterborough constituency, but has disputed the amount calculated.
The largest repayment, of £81,446, has been returned by Tory MP for Clwyd West, David Jones.
Mr Campbell was implicated in the 2009 expenses scandal, when leaked files revealed he had made second-home claims of more than £77,000 over four years.
The DUP man had also claimed £11,500 in hotel bills between 2005 and 2006, before moving into his flat in London, and racked up £4,675 on furniture and appliances including TVs and a DVD player.
It is the second financial blow this week for Mr Campbell, who represents East Londonderry at both Westminster and Stormont.
Yesterday's Queen's Speech outlined the Government's Northern Ireland Bill, which would ban him from "double-jobbing" as both MLA and MP.
Gregory Campbell said he backed the Government's decision to "bring forward legislation on dual mandates".
"As part of the new expenses system introduced at Westminster I sold a property which previously had been purchased. This sale has resulted in the taxpayer being some £60,000 better off," he said.
"At no point neither I nor any of my colleagues queried or contested the figures put forward by IPSA.
"It is also welcome that the Government has finally moved to bring forward legislation on dual mandates. This is something the DUP has called for for some years now.
"Failure to reduce the number of MLAs however will mean extra cost to the public purse as the new scenario has absolutely no financial implication for myself as I do not receive any salary for my role as an MLA, which at the moment saves significant money from the public purse."