Labour was the best-funded political party in the UK in 2013, with an income of £33.3m.
The Conservatives were in second place on £25.4m with the Lib Dems third on £7.3m, according to accounts lodged with the Electoral Commission.
The UK Independence Party doubled its income, from £1.2m in 2012, to £2.5m.
The SNP saw a slight decrease, from £2.3m to £2m, with Sinn Fein on £1.2m, the Green Party on £881,819 and the British National Party on £605,208.
Labour's income included £6.9m in public funding - most of it from the so-called Short money to help opposition parties with policy research and other costs. The Conservatives received just £659,000 in public funding.
The rest of the income is from donations, including those too small to be registered quarterly, plus money from conferences, merchandising and any sales of property and other assets.
The trade unions are major contributors to Labour coffers, but the party said funds from individual members amounted to more than £8m.
"The total increases to £10.5m with contributions from our elected representatives making funds from members our greatest income segment."
The accounts show the party has moved a step closer to clearing its record debts, which stood at £41,798,000 in 2005.
John Mills, founder of TV shopping channel JML continued to be one of Labour's biggest donors, with one non-cash donation worth £1.6m.
Labour's membership increased by nearly 2,000 to 189,531 - less than half the total in 1997, when Tony Blair won his landslide general election victory.
The Lib Dems' membership increased for the first time since 2010, with an extra 950 people joining the party, bringing the total to 43,451. Membership was 65,038 when the party entered into coalition with the Conservatives.
The party's total income was also up by more than £1m on 2012.
The Conservatives do not declare membership figures but their membership income was up slightly, from £747,000 to £749,000.
Electoral Commission chief executive Peter Wardle said: "We are pleased that, for the third year running, all the larger political parties have submitted their accounts to us by the statutory deadline.
It is essential that parties continue to be transparent with their financial information so voters can see exactly how they are funded and how this money is spent."
Here is the full list of income for parties with gross expenditure of more than £250,000:
- Labour Party - £33,336,000
- Conservative Party - £25,352,000
- Liberal Democrats - £7,303,514
- UK Independence Party - £2,479,314
- Scottish National Party - £2,038,245
- Co-operative Party - £1,187,120
- Sinn Fein - £1,161,163
- Green Party - £881,819
- Plaid Cymru - £667,718
- British National Party - £605,208
- Democratic Unionist Party - £474,147
- SDLP - £360,483
- The Socialist Party of Great Britain - £340,863