The DUP's Gregory Campbell has agreed to hand back more than £60,000 worth of profits from a taxpayer-funded home, Westminster's expenses watchdog has revealed.
Between them, six DUP MPs have agreed to hand back a total of £143,909.46 under new rules introduced in the wake of the expenses scandal.
The Independent Parliamentary Standards Authority (Ipsa) announced that 70 politicians have agreed to repay the sums, totaling almost £500,000.
It means the DUP will be handing back more than a quarter of all the money being returned, with East Londonderry MP Gregory Campbell sending back the second highest amount of £61,403.
While DUP MPs are the only ones from Northern Ireland required to hand sums back, there is no suggestion of any impropriety.
The money is being returned because of new rules brought in following public fury surrounding the MPs' expenses scandal in 2009. MPs from outside London are allowed to claim accommodation expenses to stay overnight while attending Westminster.
But instead of using hotels or renting, they previously were able to use expenses to pay mortgage interest payments on second homes.
As the property increased in value, it meant it could be sold for profit later.
The watchdog decided to ban the use of Commons expenses to pay mortgage interest in May 2010.
However, interim arrangements were put in place for MPs elected before 2010 who had already committed to mortgages.
They were allowed to keep claiming the money up until last August – as long as they agreed to return any potential capital gain.
Some 71 MPs claimed almost £1m between them over the 15-month period but the majority were not asked to make repayments, because surveyors' reports or sale prices showed that their properties had not gained in value.
However, 29 of them were asked to make payments to reflect the increased value of houses and flats – many of them in London, which had bucked the sluggish housing market prevailing in the rest of the country at the time.
Last night, Mr Campbell said: "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.
"At no point neither I nor any of my colleagues queried or contested the figures put forward by Ipsa."
MPs asked to retrun profits
These are the 71 MPs who claimed Commons expenses to pay mortgage interest rates and have now been asked to hand back any profits from their taxpayer-funded homes.
The second column shows the total interest they claimed, while the third is the amount they are due to repay.
The information was released by the Independent Parliamentary Standards Authority (Ipsa) today and the full data can be downloaded from http://www.parliamentary-standards.org.uk.
MP (Party, Constituency), Total mortgage interest claimed, Total repayment due to Ipsa:
David Anderson (Labour, Blaydon), £25,084.10, None
Henry Bellingham (Conservative, Norfolk North West), £3,337.60, None
Hazel Blears (Labour Salford and Eccles), £5,925.00, £7,644.00
Kevin Brennan (Labour, Cardiff West), £3,508.00, None
Malcolm Bruce (Lib Dem, Gordon), £1,715.03, None
Andy Burnham (Labour, Leigh), £18,952.28, £4,456.08
Lorely Burt (Lib Dem, Solihull), £5,445.71, None
Gregory Campbell (DUP, East Londonderry), £16,755.00, £61,403.18
Ronnie Campbell (Labour, Blyth Valley), £12,174.63, None
Ken Clarke (Conservative Rushcliffe), £11,597.75, £737.00
Nick Clegg (Lib Dem, Sheffield Hallam), £9,104.11, None
Michael Connarty (Labour, Linlithgow and East Falkirk), £34,168.07, £6,833.16
Mary Creagh (Labour, Wakefield), £23,647.69, None
Philip Davies (Conservative, Shipley), £15,131.50, None
John Denham (Labour, Southampton Itchen), £16,087.90, £7,894.80
Nigel Dodds (DUP, Belfast North), £25,434.16, £19,507.76
Jeffrey Donaldson (DUP, Lagan Valley), £20,338.06, £1,448.46
Brian Donohoe (Labour, Central Ayrshire), £28,308.35, £9,469.36
Frank Doran (Labour, Aberdeen North), £5,920.55, None
Alan Duncan (Conservative, Rutland and Melton), £18,229.56, None
Tobias Ellwood (Conservative, Bournemouth East), £13,508.06, None
Natascha Engel (Labour, North East Derbyshire), £17,554.04, None
Liam Fox (Conservative, North Somerset), £5,178.90, None
Hywel Francis (Labour, Aberavon), £9,955.42, £9,044.98
David Gauke (Conservative, South West Hertfordshire), £13,627.36, £26,762.76
Andrew George (Lib Dem, St Ives), £20,859.96, £22,534.20
Helen Goodman (Labour, Bishop Auckland), £17,892.50, None
Robert Goodwill (Conservative, Scarborough and Whitby), £14,585.05, £4,963.39
Peter Hain (Labour, Neath), £9,413.62, None
Philip Hammond (Conservative, Runnymede and Weybridge), £20,967.74, £34,883.54
David Hanson (Labour, Delyn), £20,800.00, None
John Hayes (Conservative, South Holland and The Deepings), £15,125.92, None
Mark Hendrick (Labour/Co-op, Preston), £7,332.50, None
Mark Hoban (Conservative, Fareham), £17,247.40, £11,332.00
Stewart Hosie (SNP, Dundee East), £13,899.26, None
Stewart Jackson (Conservative, Peterborough), £32,494.86, £54,000.00
David Jones (Conservative, Clwyd West), £18,060.83, £81,446.00
Elfyn Llwyd (PC, Dwyfor Meirionnydd), £3,102.54, None
Anne Main (Conservative, St Albans), £7,755.20, None
William McCrea (DUP, South Antrim), £6,929.91, £29,793.60
Pat McFadden (Labour, Wolverhampton South East), £14,137.48, None
Michael Meacher (Labour, Oldham West and Royton), £1,642.26, None
David Miliband (Labour, formerly South Shields), £5,903.80, None
Andrew Mitchell (Conservative, Sutton Coldfield), £19,905.26, None
Austin Mitchell (Labour, Great Grimsby), £4,788.83, None
Paul Murphy (Labour, Torfaen), £6,429.70, None
Stephen O'Brien (Conservative, Eddisbury), £6,834.06, None
James Paice (Conservative, South East Cambridgeshire), £11,310.76, £9,177.12
Owen Paterson (Conservative, North Shropshire), £25,634.28, £7,755.05
Jamie Reed (Labour, Copeland), £12,436.79, None
Linda Riordan (Labour/Co-op, Halifax), £10,007.23, None
Angus Robertson (SNP, Moray), £2,993.43, None
Laurence Robertson (Conservative, Tewkesbury), £28,439.51, None
Dan Rogerson (Lib Dem, North Cornwall), £1,250.06, None
Alison Seabeck (Labour, Plymouth, Moor View), £15,627.22, None
Jim Sheridan (Labour, Paisley and Renfrewshire North), £7,126.90, None
David Simpson (DUP, Upper Bann), £11,208.65, £30,308.40
Marsha Singh (Labour, Bradford West), £1,201.34, None
Andrew Smith (Labour, Oxford East), £6,840.62, £3,933.72
Angela Smith (Labour, Penistone and Stocksbridge), £6,680.76, £8,496.00
Peter Soulsby (Labour, formerly Leicester South), £6,250.00, £2,828.84
Edward Vaizey (Conservative, Wantage), £17,226.46, None
Ben Wallace (Conservative, Wyre and Preston North), £4,802.37, None
Steve Webb (Lib Dem, Thornbury and Yate), £28,668.77, None
Alan Whitehead (Labour, Southampton Test), £4,986.24, £3,339.15
John Whittingdale (Conservative, Maldon), £4,539.17, £12,441.00
David Willetts (Conservative, Havant), £2,912.00, £7,730.74
Hywel Williams (PC, Arfon), £7,474.97, None
Sammy Wilson (DUP, East Antrim), £19,633.90, £1,448.46
Tim Yeo (Conservative, South Suffolf), £19,913.06, £3,215.74
George Young (Conservative, North West Hampshire), £22,197.75, None