Labour leadership contest: After 88 days of campaigning, how did Labour's candidates do?

After 88 days, nearly two dozen debates and countless meetings to woo the party faithful, by midday on 12 September Labour will have a new leader.

Most believe that it will be Jeremy Corbyn – but thanks to Labour’s complex electoral system, he could still be beaten by either Yvette Cooper or Andy Burnham.

One thing is certain though: this has been a surprisingly substantive and energising campaign that has engaged thousands of people in a passionate debate about the future of the left in Britain.

So how have the respective campaigns and candidates performed?

Jeremy Corbyn

When he made it on to the Labour leadership ballot with just minutes to spare, no-one, including himself, gave the veteran left-winger any hope. As one senior Corbyn campaign aide put it: “Victory for us was not coming last.”

So how has he ended up the favourite? In part, Mr Corbyn’s success can be attributed to Andy Burnham’s failure to secure his position as the candidate of the left by changing his position on welfare reform while trying to simultaneously woo the right of the party.

This opened up space that Mr Corbyn’s campaign capitalised on. He also benefited from a distinctive message on austerity, financial and logistical support from the unions, and being the candidate who seemed “fresh” compared with his better known rivals.

As the campaign took off – and polls showed that he could win – he was also able to take advantage of Labour’s new leadership rules which allowed the public to sign up to vote for just £3. These new supporters now account for a fifth of the total electorate and most are supporting him.

Liz Kendall

When Chuka Umunna pulled out of the race, some in the Westminster Village thought Ms Kendall would be the “fresh face”, and the “Blairite” rival to Andy Burnham.But a series of unforced errors put paid to that. Her decision to back Tory plans to spend 2 per cent of GDP on defence went down like a lead balloon with party members, as did her decision to come out in favour of free schools. Within weeks, her campaigners admitted they were likely to come last. But things have improved. She has won plaudits for sticking to her “modernising” message in the face of an unpleasant and personal campaign against her.

And while she says she will not serve in a Corbyn cabinet, she has a future as a leading voice of Labour “moderates”.

Yvette Cooper

Ms Cooper began her campaign too cautiously and was encumbered both by her marriage (to the divisive Ed Balls) and a feeling that she did not represent a break with the Blair/Brown era.

At first she appeared keener not to offend than offer any clear vision of her own beliefs. She also suffered from a lack of support from the party, most of whom threw their weight behind Mr Burnham in a belief that he would win.

But the Corbyn surge was the making of her. Unlike Mr Burnham, she decided to face Mr Corbyn and his policies head on, and her speech attacking the left-winger’s vision for Labour was a stand-out moment of the campaign.

She also won deserved plaudits for being the first politician to call for Britain to accept 10,000 Syrian refugees – before the issue came to such prominence.

Andy Burnham

In a message to his supporters, Andy Burnham said he knew “one thing” – which was that his campaign “couldn’t have done any more” to win the leadership.

It is not a sentiment shared by many MPs in the party, who lined up to back him because they thought he was the inevitable winner. The shadow Health Secretary has, undeniably, underperformed.

At the start, he took it for granted that he would get union support, so pivoted to the right to try and maximise his vote. When the Corbyn surge emerged, he pivoted back again to try and shore up his base. It has left him seen as the candidate whose ambition trumped political principle, in a race where, thanks to Corbyn, principles became more important than electability. He could still win, but that will be despite of rather than because of the past months.

Early on Saturday morning, a man called Iain McNicol will become the first person to discover the identity of Labour’s next leader.

As returning officer and Labour’s General Secretary, he will “press the button” on a computer programme which will process around 500,000 votes cast and calculate the final result.

Within a few seconds, he will know whether Jeremy Corbyn has pulled off a victory that would have been inconceivable just a few months ago, or whether Andy Burnham or Yvette Cooper can clinch an unlikely win.

But while the result will take just a few moments to emerge, the system that Labour has used to elect its next leader will remain under scrutiny for much longer.

Under the fiendishly complicated system put in place by Ed Miliband, the electorate is divided into three groups: 292,000 members, 148,000 union “affiliates” and 112,000 registered supporters who each paid £3 to take part.

Each voter had to place the four candidates in order of preference, with the candidate that got the least first preferences getting eliminated, until one candidate gets an overall majority.

Most people expect that Jeremy Corbyn will be comfortably ahead when the first round preferences are announced. But unless he gets over the 50 per cent mark, one candidate – almost certainly Liz Kendall – will be eliminated.

Her votes will then be redistributed. Given Kendall is the candidate of the right, very few of her votes will go to Corbyn and the contest is likely to go to another round.

At that stage either Andy Burnham or Yvette Cooper will be eliminated – and that will depend much on who Kendall’s supporters give their second preferences to.

It is perfectly possible, for example, that Cooper could come third in the first round then leapfrog Burnham in the second for a final head-to-head against Corbyn. It could also be the other way round.

Not only that, many suspect Corbyn’s main support will be among registered supporters and union affiliates. So it is perfectly possible that he will be the eventual winner – but not command the support of party members.

The divisions will be instantly visible on the massive screens at the QEII Conference Centre in London where the result will be announced in front of an audience of around 1,000 Labour members.

As returning officer, Mr McNicol will reveal the results to the candidates shortly before the event starts at 11am. He will then take to the stage to announce the result of the deputy leadership before moving onto the main event.

He will take each round of voting in order – revealing the split between each segment of the electorate.

Eventually a winner will be declared and he or she will make a short victory speech before embarking on a round of media interviews. Their life will never be quite the same again.