When is the vote happening?
Ballots close on 10th September, with a conference to announce the results two days later.
Who is running?
The current candidates are:
Andy Burnham Shadow Health Secretary, MP for Leigh
Yvette Cooper Shadow Home Secretary, MP for Normanton, Pontefract and Castleford
Jeremy Corbyn MP for Islington North
Liz Kendall Shadow Minister for Care and Older People, MP for Leicester West
Who will win?
Left-leaning Jeremy Corbyn is the bookies' favourite - and has polled well above his rivals.