Labour raised a record income of nearly £56 million in 2017, official figures show.
Jeremy Corbyn’s party took in just over £4.5 million more than its previous record of £51,153,000 in 2015.
Labour both raised and spent about £10 million more than the Conservatives, with income of £55,793,000 and a spend of £54,342,000 in 2017.
A party spokesman said: “Unlike the Tories, who rely on a few super-rich donors to bankroll them, we’re proud to be powered by small donations from hundreds of thousands of people across the country.”
Accounts for Theresa May’s party show it took in a much lower £45,947,000 and spent £44,867,000.
Legacy payments from dead Conservative donors were double those from living members, with £1,697,000 paid in legacies versus £835,000 from memberships.
Conservative membership payments have halved from £1,459,000 a year earlier and legacies were more than five times higher, jumping from £301,000.
In contrast, Labour saw membership payments rise from £14,393,000 in 2016 to £16,165,000 in 2017.
No other political party raised more than £10 million, with the Liberal Democrats in third place, taking in £9,710,000 but spending £10,454,000.
The SNP raised £5,800,000 and spent £5,098,000.
SNP depute leader Keith Brown said: “It’s clear the Tories are being kept afloat by a tiny group of super-rich donors to survive.
“With thousands more people joining the SNP in the wake of the Westminster walk-out in June, it looks like we’re on the cusp of overtaking the Tories to become the second largest party in the UK.”
Spending by all political parties soared 30% in 2017 compared to the year before, Electoral Commission figures show.
The snap general election saw parties spend nearly £28 million more than in 2016.
Income for parties rose slightly less by just over £24 million – a rise of 24%.
Figures are for the 10 political parties that raised more than £250,000 for the year ending December 31.