The deadline to register to vote in Labour’s leadership contest is approaching as thousands of new members prepare to have their say.
The party’s website crashed earlier following a last minute call on social media by supporters of left wing candidate Jeremy Corbyn.
The party apologised for the problems and the site is now working.
Labour has also reassured candidates amid fears the process is being sabotaged by members of other parties.
Latest figures show almost 450,000 people are eligible to vote in the contest – party officials said 1,200 applications had been rejected as bogus.
The party said it had 282,000 full members – an increase of more than 80,000 since the general election defeat.
A further 70,000 people have become registered supporters, meaning they are able to take part in the vote for a £3 fee if they agree they “support the aims and values of the Labour Party”.
There are also 92,000 “affiliated supporters”, largely trade union members.
Many of these people, including most of the affiliated supporters category, are “awaiting verification”, Labour says.
Ballot papers will begin to be sent out on Friday, and the result will be announced at a special conference on 12 September.
Labour leadership contest
Who are the candidates? Andy Burnham, Yvette Cooper, Jeremy Corbyn, Liz Kendall
Dates: Ballot papers will be sent out on 14 August; voting can take place by post or online. They must be returned by 10 September. The result is announced on 12 September
Who can vote? All party members, registered supporters and affiliated supporters – including those joining via a union
What is the voting system? The Alternative Vote system is being used so voters are asked to rank candidates in order of preference
How does it work? If no candidate gets 50% of all votes cast, the candidate in fourth place is eliminated. Their second preference votes are then redistributed among the remaining three. If there is still no winner, the third place candidate is eliminated with their second preferences (or third in the case of votes transferred from the fourth place candidates) redistributed. It is then a head-to-head between the last two candidates
At-a-glance profiles of the four contenders
Rochdale MP Simon Danczuk followed John Mann, Graham Stringer and Barry Sheerman in criticised the voting process and calling for a rethink.
He said he believed the process may have to be rerun and warned that if Mr Corbyn wins he would not be able to command discipline amongst Labour MPs – many of whom would not vote for “crazy left-wing stuff”.
Labour has dismissed such calls, and says it has a robust system in place to detect non-party supporters who are attempting to vote.