Donations to political parties fell by almost £1m during the second quarter of this year, official figures show.
The Electoral Commission said £7,873,478 in funding had been reported - down £992,312 on the first three months of the year.
The Conservatives received £3,785,579, Labour £2,964,471 and the Liberal Democrats £717,797.
Labour's biggest donor was the Unite union, while the Conservatives' was financier Michael Farmer.
After the three main parties, the Green Party received the most donations, totalling £180,060.
Next was the British National Party, with £100,000, followed by the Co-operative Party, on £76,200, and the UK Independence Party, on £29,370.
Plaid Cymru received £17,500 and the Scottish National Party £2,500.
Among its donations, Labour was given £840,275 by Unite, £429,558 by the Union of Shop, Distributive and Allied Workers (USDAW) and £313,863 by the GMB union.
Mr Farmer, who was appointed the Conservatives' co-treasurer in February, gave the party £512,450.
The Liberal Democrats' largest donation was £250,000 from Brompton Capital Limited, a property development company owned by entrepreneur Rumi Verjee, who last year dined with party leader Nick Clegg at his grace and favour residence Chevening, in Kent.
The largest individual donor was Lib Dem peer Lord Loomba, who gave £100,000. The Lib Dems also received £350,440 in public funds.
The Labour Party received £1,640,198 in public money, as part of a longstanding scheme to aid opposition parties.
The Conservatives were given £27,377 in public money, as a result of being in opposition in Scotland.
The commission also said political parties owed £14.6m in outstanding loans, a slight fall on the figure for the first quarter of the year.