More than 180,000 sign up to vote in Labour election
The surge in applications occurred in just 48 hours, with members paying £25 to vote.
In total, there have been 183,541 applications made to the Labour Party in the last 48 hours, to sign up as registered supporters.
Registered supporters who paid the £25 fee will have the right to vote in the upcoming leadership election between current leader Jeremy Corbyn, and Labour MP Owen Smith.
The vote is also open to those who joined before January 12, as well as affiliated supporters from unions and other organisations.
A spokesman for Mr Corbyn said it was "reasonable to assume" that a large amount of new registrations come from supporters of the veteran MP.