This article originally implied that the Conservative party received only slightly more income from membership fees than UKIP. This was based on submissions that UK political parties are required to make to the Electoral Commission.
However, these submissions only take into account membership fees that are paid directly to the central party. Although the majority of UKIP membership fees are paid to the central party, this is not the case with the Conservatives.
Many Conservative associations receive substantial income in membership fees which are not declared in this particular set of EC figures. We are happy to make this clear.
UKIP has drawn level with the Conservatives in terms of how much income its national party earns from membership subscriptions.
The new figures, released by the Electoral Commission today, support the idea expressed by some Conservatives that the party's activists have deserted it for the upstart eurosceptic party. UKIP's membership income grew 63% between 2012 and 2013.
Tory local parties have reported members citing same-sex marriage, immigration, and David Cameron's position on Europe as reasons for them deserting the party. The figures come on the same day as the launch of a new immigration policy by David Cameron to attract to former supporters back to the Tory fold.
UKIP's national membership income has grown dramatically over the last three years, while the Tories' has declined.
UKIP's members paid its national level party subscriptions of £714,492 in 2013, while Conservatives paid a total of £749,000. Tory members are now paying only 5% more into central party coffers than UKIP.
The figures were released by the Electoral Commission as part of the latest set of annual party accounts.
The Conservatives still have more members than UKIP, but the gap appears to be narrowing.
Party membership numbers aren't recorded independently, and parties' own estimates are notoriously unreliable. At the end of last year the Conservatives said they had 134,000 members. UKIP claimed their own membership was 32,500.
The figures suggest a dramatic increase in the number of people joining UKIP. A normal Conservative party membership costs £25 a year, while UKIP charges £30.
The discrepancy between the number of members in each party and the amount of membership money going into central party coffers is largely because UKIP and the Tories split membership subscriptions between central and local parties in different ways.
The amount of money central parties raise from their members is important in the run-up to the general election, where party warchests are expected to be decisive.
A UKIP spokesperson told BuzzFeed the party was "defying the trend amongst the old legacy parties and "re-engaging people in politics". "As a result we have a growing membership and activist base," he added.