and who would you like to win?
The first votes in Labour's leadership contest are due to be cast, with ballot papers expected to arrive by post on Monday morning.
Left-winger Jeremy Corbyn is still regarded as a clear favourite, by his opponents and by bookmakers.
Rival candidate Andy Burnham will announce later that he wants to involve Mr Corbyn in rebuilding the party.
Former PM Gordon Brown has said Labour must be "credible" and "electable" in order to win back power.
Everything you need to know about the four candidates hoping to become the next Labour leader
The other two candidates in the contest are Yvette Cooper and Liz Kendall.
it looks to me that Jeremy Corbyn will win