MPs owe the House of Commons almost £140,000 in unpaid food and drink bills, it has been revealed.
The House authorities are chasing cash from more than half of all MPs for wining, dining and entertaining in Parliament's restaurants.
They include 77 MPs who have failed to settle their tabs - averaging more than £500 each - for more than six months.
The TaxPayers' Alliance said it was unacceptable that MPs left their debts to the public purse unpaid for so long.
Food and drink in the Commons is already subsidised by the taxpayer to the tune of £6.1 million a year.
The details of MPs' debts were obtained from the Commons by the Press Association under the Freedom of Information Act.
They showed that in August, 329 MPs owed a total of £138,046 in entertainment and catering - an average of £419 each.
Some £45,150 of that had been due from 77 MPs for more than six months.
The figures include MPs' liabilities from events they have sponsored - giving third parties such as constituents access to Parliamentary facilities - as well as personal bills.
The Commons also revealed that another £10,018 was owed by 52 MPs in overpaid salaries and allowances.
That included £4,229 outstanding from 20 MPs for more than six months.
These figures are distinct from the hundreds of thousands of pounds of dubious claims paid back by MPs in the wake of the expenses scandal.
Matthew Elliott, chief executive of the TaxPayers' Alliance, said: "It's simply unacceptable for MPs to leave their debts to the taxpayer unpaid for so long.
"We've heard a lot of rhetoric from the Government and Opposition benches about the importance of everyone paying invoices swiftly in the recession, but it seems that many of them don't practice what they preach.
"It is bad enough that these bars and restaurants are already heavily subsidised, without MPs eating and drinking on a tab and then leaving bills unpaid.
"Public spending in all areas needs to be brought under tighter control, and that should start at the top."