There have been a series of party funding controversies over the years Conservative, Labour, Lib Dem, Green and union figures are addressing the final session of an inquiry into political party funding.
Tory co-chairman Lord Feldman, union chief Bob Crow, Lib Dem chief executive Chris Fox and Labour general secretary Ray Collins will give evidence.
The Committee on Standards in Public Life is investigating options to reform party funding.
But the issue has proved contentious – cross-party talks broke down in 2007.
All the main parties pledged to do something about party funding before the election and all said they agreed with moves to cap funding, as part of a reform package.
The standards’ watchdog’s final day of the public hearings in Westminster will also hear from Green Party deputy leader Adrian Ramsay, Labour MP Graham Allen and the Liberal Democrats’ head of compliance David Allworthy. The committee aims to produce a report in the spring.
A previous committee’s recommendations helped set the current party funding framework 10 years ago.
But opening the hearings last November chairman Sir Christopher Kelly said times had moved on and there had been a “number of unintended consequences” – including the “big donor culture”.
Political parties are funded from a combination of membership subscriptions, donations, union money, loans, and public funds.
There have been a series of controversies over the years – from donations made to Labour by a property developer under other people’s names and the tax status of one of the Conservatives’ biggest donors – Lord Ashcroft.
There has already been an effort to reach an agreement on reforming party funding – in 2006 another review was launched, in the wake of the cash-for-honours row and the revelation that parties received large undisclosed loans in the run-up to the 2005 election.
But talks were abandoned in October 2007 as parties clashed over Labour’s trade union funding and Lord Ashcroft’s funding of Tory candidates in marginal seats.
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