George Galloway was Parliament's most expensive backbencher on the basis of his voting record between 2001 and 2004, says a report.
Mr Galloway is still in the Big Brother house
A London School of Economics study of MPs' expenses says Mr Galloway, a Labour MP at the time, cost £1,491 for every vote he cast.
Tony Blair was among four ministers who cost more than Mr Galloway - but the report points to their other duties.
Overall, MPs' expenses are "mostly justifiable", say the academics.
Mr Galloway, who is currently appearing in Channel 4's Celebrity Big Brother, finished fifth in the table of most expensive MPs on their voting record.
His total expenses bill was about average for MPs - 333rd out of 659 - but his voting record made him more costly, says the report.
Mr Galloway was MP for Glasgow Kelvin during the time covered by the study. He is now Respect's MP for Bethnal Green and Bow, in London.
He was behind Mr Blair, who claimed £3,360 in expenses for each Commons vote, Chancellor Gordon Brown (£3,114), Foreign Secretary Jack Straw (£2,043) and then Energy Minister Brian Wilson (£1,596).
Other "expensive" MPs included Labour backbench committee chairman Gwyneth Dunwoody (£1,187 per vote), Conservative Michael Mates, a member of the intelligence and security committee, (£1,070) and SNP leader Alex Salmond (£1,043).
The report found that MPs with constituencies far from Westminster tended to claim more expenses due to the cost of travelling to and from London.
But party affiliation, constituency size, average income of the constituency and whether a seat is marginal in electoral terms are all unrelated to the total amounts claimed, it says.
Authors Timothy Besley and Valentino Larcinese said it was "not surprising" that senior ministers cost more because their responsibilities could prevent them voting.
The average MP's vote cost £556 in expenses, while the cheapest cost just £257, said the report. But each minister's vote cost £545 more than a backbencher's.
The academics say their figures are a "crude" measure but may not be cruder than performance indicators used for other parts of the public sector.
Dr Larcinese said: "Up until now MPs have not themselves been subject to performance targets. But this raises the wider issue of whether (as public servants) they should.
"Our findings show that the allowance system does seem to fulfil its main purposes of levelling the playing field between MPs with different circumstances and providing MPs with the means to improve the quality of their service."