Labour and the Conservatives have attacked each other over political funding, saying their rivals are in the pockets of their donors.

After a brief Christmas ceasefire, the government and the opposition are back at each other's throats.

Labour says the Tories received £110,000 from just six "blue chip" companies in the past financial year alone.

But the Conservatives have responded by saying the government used its patronage to reward individuals who have given money to Labour.

Both parties have produced research to support their positions.

The Tories point to figures such as Lord Puttnam, Mick Hucknall and Lord Haskins, who have donated more than £5,000 to the Labour Party and now have positions on government task forces.

The Labour paper said five of the party's company backers - Slough Estates, IMI, Tarmac, Singer and Friedlander, and Caledonia Investments - had directors with close links to the Conservative Party.

Attacking Labour, shadow cabinet office minister Andrew Lansley said such donations accounted for less than 2% of Conservative Party income, compared to 40% of Labour's income from trade unions.

Labour was guilty of a "culture of cronyism", he added.

Mr Lansley said Labour had increased the number of task forces and public bodies but the real injury was to the public.

He said: "There are 318 of these taskforces, costing the public £20m.

"Most of the appointments are not made according to the Nolan [Committee on Standards in Public Life] rules, the independent appointment rules set up under the Conservative administration.

'Culture of cronyism'

"We find when we look at the membership of many of these taskforces that they are people with connections to Labour so it propagates this culture of cronyism, the idea that the only way you can influence government policy, Labour policy, is to be a Labour supporter or Labour donor.

"In the Conservative Party it has never been the case that giving donations to the Conservative Party gave influence over policy."

But Cabinet Office minister Ian McCartney denied suggestions of cronyism.

He said: "The Labour Party is about promoting people of talent, he didn't mention the fact that Michael Heseltine has had a job under Labour, Alastair Goodlad, Tony Newton, David Mellor - all former Tory cabinet ministers.

"The Labour Party is about promoting people of worth and giving people opportunities and changing the system of appointments."

"The issue today is about how we have revealed this cosy club of business people who don't use their own money, but their company's money without even referring it back to their shareholders, to keep the Tory Party afloat.

"That's the real issue, about cleaning up British politics from the mess left by the last Tory government."

McCartney said a handful of businessmen have got the "Conservative Party lock, stock and barrel".

He said: "That's why we're going to change the law in the new year. We're going to ensure those companies consult their shareholders before they make political donations.

"I think that's important that we open up the whole process of transparency in political funding of all political parties.