The Labour Party has seen its membership surge to record levels in the wake of the EU referendum and the challenge to Jeremy Corbyn's leadership.
However, there was a huge outcry among those who'd just joined after the party's National Executive Committee (NEC) changed the rules so only those who have been members for at least six months can vote in the leadership contest.
There are other ways voters can have their say - but they need to act fast.
The Week
Escape your echo chamber. Get the facts behind the news, plus analysis from multiple perspectives.
SUBSCRIBE & SAVE
Sign up for The Week's Free Newsletters
Join more than 350,000 subscribers and keep yourself informed with a selection of The Week’s most interesting, enlightening and entertaining stories - plus daily puzzles.
Join more than 350,000 subscribers and keep yourself informed with a selection of The Week’s most interesting, enlightening and entertaining stories - plus daily puzzles.
Latest Videos FromThe Week
Here's everything you need to know about the contest and how you can cast your vote:
Why are so many people joining?
Corbyn's leadership is under threat after most of his shadow cabinet stood down and he lost a vote of no confidence. However, he has refused to resign, citing his huge support among grassroots members.
Angela Eagle triggered the leadership contest last week with her campaign to head the party. She and rival Owen Smith are now reportedly battling it out to decide who will stand in the contest, with the final contender due to be announced tomorrow.
It is thought many of the new members have joined with the "express intention" of defying MPs and supporting Corbyn, says The Independent.
This is backed up by a new YouGov poll of party members showing Corbyn has a lead of more than 20 points over both his rivals and that his net approval rating has gone up in the last three weeks.
The veteran politician is widely expected to win a majority of the vote among rank-and-file members.
"If this happened, his success and the 100,000 membership surge would mirror the events of [last] September's leadership election," the Independent reports.
Who can vote in the leadership election?
- Labour members who joined the party on or before 12 January
- Anyone who becomes a "registered supporter" by making a one-off payment of £25. There is only a 48-hour window to do this - which opened at 5pm on Monday 18 July and closes at 5pm on Wednesday 20 July. You can register here.
- Members of affiliated trade unions and other organisations who have been a member of that organisation on or before the 12 January 2016 and signed up as an "affiliated supporter" before 8 August 2016.
Who can apply to become a party member?
Anyone who has British or Irish citizenship or who has lived in the UK for at least one year and is not a member of any other political party.
How do I join?
There are several ways: you can do so by telephone, online or by post. To join over the phone, call 0345 092 2299 and follow the steps. A membership form can also be filled in and submitted on the Labour Party website or printed out here and posted to Freepost RSJK–BART–AYRZ, Labour Party Membership, Cramlington NE23 1BB.
How much is it and where does the money go?
The cost varies from as little as £1 a month for students and young people to a standard rate of £3.92 a month. Discounts are also given to pensioners, the unemployed and trade union members affiliated to the party.
"Unlike the Tories, we don't rely on a small number of super-wealthy donors," says the party. "We rely on funds from our dedicated members and your membership fee would provide a vital boost to our campaigning efforts."
What does membership achieve?
You receive a membership pack, regular newsletters and invitations to local events and meetings. Crucially, you will be able to vote in future leadership elections and on party policy, as well as stand as a candidate yourself.
