Following the Labour Party's defeat at the general election on 7 May 2015, Ed Miliband resigned as its party leader.
His resignation caused the party to have a leadership election.

On 2 June, it was reported in media sources that Corbyn was thinking of applying to be a candidate.
The next day, Corbyn announced to his local newspaper, The Islington Tribune, that he would become a candidate in the election.
Before he could become a candidate he had to secure at least 35 nominations from MPs.
In the end he got 36.
Some of the MPs who nominated him didn't think he would win and only nominated him to have a 'broader debate'.

Some, including former foreign secretary Margaret Becket, told journalists they regretted the decision.
When he was accepted as a candidate Corbyn said: "This decision is in response to an overwhelming call by Labour Party members who want to see a broader range of candidates and a thorough debate about the future of the party.
I am standing to give Labour Party members a voice in this debate".
He would run against candidates Yvette Cooper, Andy Burnham and Liz Kendall.

Corbyn was elected party leader in a landslide victory on 12 September 2015 with 59.5% of first-preference votes in the first round of voting.
It has been said that Corbyn would have won in the first round with 51% of votes.
Corbyn's 40.5% majority was larger than that won by Tony Blair in 1994.
Following the Labour Party's defeat at the general election on 7 May 2015, Ed Miliband resigned as its party leader. His resignation caused the party to have a leadership election.
On 2 June, it was reported in media sources that Corbyn was thinking of applying to be a candidate. The next day, Corbyn announced to his local newspaper, The Islington Tribune, that he would become a candidate in the election. Before he could become a candidate he had to secure at least 35 nominations from MPs. In the end he got 36. Some of the MPs who nominated him didn't think he would win and only nominated him to have a 'broader debate'.
Some, including former foreign secretary Margaret Becket, told journalists they regretted the decision. When he was accepted as a candidate Corbyn said: "This decision is in response to an overwhelming call by Labour Party members who want to see a broader range of candidates and a thorough debate about the future of the party. I am standing to give Labour Party members a voice in this debate". He would run against candidates Yvette Cooper, Andy Burnham and Liz Kendall.
Corbyn was elected party leader in a landslide victory on 12 September 2015 with 59.5% of first-preference votes in the first round of voting. It has been said that Corbyn would have won in the first round with 51% of votes. Corbyn's 40.5% majority was larger than that won by Tony Blair in 1994.
Jeremy Corbyn