Following Ed Milliband's resignation as party leader after the election, any potential candidates had until noon on Monday to gain the 35 nominations from the Parliamentary Labour Party in order to be accepted as candidates for the leadership of the party.
At the close of nominations, four people stood duly nominated:
Currently the bookies' favourite to win, he comes from the centre of the party, and has been an MP since 2001.
A former chief secretary to the treasury, Cooper has been shadow home secretary - and a thorn in the side of Theresa May - for the past four years.
The standard bearer for the left of the party, Corbyn obtained the required amount of nominations with just 2 minutes to go before close of nominations following a strong grass roots campaign, he intends to be the "anti-austerity" voice in the debate about Labour's future leadership.
MP for Leicester West since 2010, Kendall is seen as the "Blairite" candidate, and has already caused controversy by saying that Labour "should be less reliant on funding from the unions".
It looks to be a fascinating contest, with the inclusion of Jeremy Corbyn moving the contest from being between candidates with similar ideologies to a real debate with all sides of the party represented. Burnham, Cooper & Kendall are going to have to think very carefully about how they appeal to the left of the party if they want to get any significant grass roots vote.
I'm firmly behind Jeremy Corbyn - he's a complete change from the leaders of the last 20 years, and will bring the party back to socialism, and provide a real alternative to the Conservatives in 2020.