Four MP couples caught cashing in on taxpayer-funded housing allowances in latest expenses scandal

They are eligible for double the money other MPs get - even though they share a property.

Scroll down for more...

The couples - who include Cabinet duo Ed Balls and Yvette Cooper - are using a loophole which pays up to £22,000 a year to each of them to fund a second home.

The revelation added to calls for an end to the expenses gravy train.

And it came as Gordon Brown and David Cameron instructed their MPs to account publicly for every detail of their expenses, including naming family members on the payroll.

The Prime Minister and Tory leader were forced to act after the uproar over Derek Conway's misuse of public funds in employing his student sons as researchers.

Mr Cameron said all 96 Tory frontbenchers would be forced to record details of their office and housing allowances from April, which will be published in July.

He made it clear he expected all backbenchers - more than 100 - to follow suit.

But Mr Brown insisted all his MPs would declare expenses details as soon as possible and, unlike Mr Cameron's plan, do so retrospectively.

Yet despite the decision by Labour and the Tories to come clean, the expenses row deepened as the extent to which MP couples enjoy State-funded perks was exposed.

Mr Cameron expressed unease at the way the husband and wife teams are able to submit separate claims of up to £44,000 for the same home.

He suggested second-home perks - known as the additional costs allowance - could be axed in favour of higher salaries for MPs.

Sleaze watchdogs have been asked to investigate the financial arrangements of Mr Balls and Miss Cooper, the Cabinet "golden couple".

They claim £15,979 and £15,995 - a total of £31,974 - for covering the cost of the same London home.

Three more couples also face questions over why they are submitting separate housing allowance claims when they live together.

Senior Tory backbenchers Sir Nicholas and Ann Winterton claimed £14,797 and £18,211 last year - a total of £33,008.

The couple are also under fire over the way they have claimed the second home perk to pay rent on their London flat - which they had already bought and transferred into a family trust.

This is within Commons rules, but critics say they are using the loophole to avoid inheritance tax. They have claimed £165,000 over five years.

Mr Cameron yesterday described the Wintertons' behaviour as "indefensible", adding: "We have to be clear any arrangements we enter into are ones we are prepared to protect and defend in a court of public opinion.

"I think it is difficult to do that in their case."

Labour's Alan and Ann Keen submitted separate claims of £19,814 and £18,701 - a total of £38,515.

They share a flat in Covent Garden, as well as a house in Brentford, West London. They did not respond to calls last night.

Peter and Iris Robinson, of the Democratic Unionists, last year submitted separate claims for £19,558 and £20,386.

They share a home in East Belfast and a flat in Docklands, East London.