Betting signals strongly indicate that Keir Starmer and Angela Rayner will be unveiled as Labour's new leadership team on Saturday. However as these six historic examples demonstrate, the favourite doesn't always win...
"Given how late we are into the current race, Labour’s 2007 deputy contest offers the best hope for those cheering an upset. On the day the result was announced, Alan Johnson was a [1.1] chance"
For weeks, the markets for Next Labour Leader and Next Deputy Labour Leader have been stagnant. It is assumed that Keir Starmer and Angela Rayner will win, as respective odds of [1.02] and [1.01] illustrate. I've no reason to expect an upset but were the market to be proved wrong, it would not be the first time by any means.
2001: IDS stuns his more famous rivals
The first big leadership contest after Betfair was invented produced a remarkable betting heat that remains fresh in the memory. Michael Portillo - then Shadow Chancellor and long tipped as a future Conservative Party leader - started a strong odds-on favourite. His principal opponent was assumed to be another Tory 'Big Beast' - former Chancellor Ken Clarke.
Both had big press endorsements and a vast name recognition advantage over their three opponents. Despite securing plenty of endorsements from Eurosceptic MPs, punters and (critically) headline writers took little notice of Iain Duncan Smith - who had been rising up the party ranks in the Shadow Cabinet. Even as the field whittled to three, IDS remained a [30.0] chance.
Then in the final round of voting among MPs, amid rumours of tactical skullduggery, Portillo was eliminated. Now it was down to the party's largely Eurosceptic members to choose. Clarke started a strong favourite around [1.4] but gradually the market wised up to the fact the grassroots preferred ideological purity to perceived electability. IDS would go on to win by a whopping 61-39 margin.
2007: Harman edges Johnson in photo finish
Given how late we are into the current race, Labour's 2007 deputy contest probably offers the best hope for those cheering an upset. On the day the result was announced, Alan Johnson was a [1.1] chance to succeed John Prescott. There was very little indication of the drama about to unfold.
Harman had started out as the outsider of six, trading around [16.0]. She only finished third in the opening round of the Alternative Vote process - Johnson led after rounds two, three and four. However, she overtook him at the death, winning by a minute 50.4 - 49.6% margin.
2008: McCain defies cash shortfall in GOP race
John McCain had been touted for at least a decade as a likely nominee for the Republicans. He lost to George W Bush in 2000 and started out as second favourite behind Rudy Giuliani when the party sought his successor in 2008.
It didn't start well. Struggling to raise cash to compete with the likes of Giuliani and Mitt Romney, McCain sacked several advisors the previous autumn and was rumoured to be quitting. Fred Thompson also usurped him in the betting and the Arizona Senator drifted out to around [25.0].
The turning point came in Iowa. Although never expected to win this socially conservative state, McCain performed respectably in fourth, way better than Giuliani, while Romney's defeat to Mike Huckabee damaged his credibility. One week later, McCain won New Hampshire and once the war hero had exorcised a ghost from his 2000 defeat in South Carolina, the result was never in doubt.
2010: Ed wins battle of the Milibands
As in that 2007 deputy contest, the race to succeed Gordon Brown threw up a late surprise - proving once again how Labour's internal dynamics can be hard to read. David Miliband had started odds-on favourite from the start and remained so until the final days of the contest.
He would win two of the three segments in Labour's electoral college - MPs/MEPs and party members - by 54/46 and 53/47 margins. The affiliate section, however, was more eager for change. David represented 'continuity New Labour' whereas his younger brother Ed said they needed to admit mistakes such as the Iraq war, tuition fees and generally tack to the Left.
Ed was subsequently boosted by endorsements by trade unions, enabling a resounding 60-40 win among affiliates, to edge David out 50.7-49.3 overall. Many believe to this day that - echoing the IDS experience - this choice of purity over electability cost the party dear.
2015: Corbyn stuns the commentariat
When Jeremy Corbyn first threw his name into the ring to replace Miliband, his candidacy was widely regarded as a joke. Odds in excess of [100.0] were available. However a grassroots drive to get him on the ballot encouraged MPs supporting alternative candidates to support his bid, in order to widen the debate. Some would later bitterly regret that generosity.
When Corbyn qualified for the final round, he was still a [24.0] chance on Betfair. Even after various online polls, and dominant hustings performances, few took him seriously at odds around [16.0] - compared to Andy Burnham and Liz Kendall. Slowly over the summer, reality dawned on a shocked media. By August, he had become favourite.
As it turned out the early betting signals could not have been more wrong. Corbyn won with 59.5%. Burnham finished second with less than a third of his share. Kendall - an early [3.5] chance - earned a mere 4.5%.
2016: Trump destroys the GOP establishment
Although the direct opposite politically, Trump's takeover of the Republicans was rather similar to Corbyn and Labour. An outsider candidate, whose candidacy was laughed off for months. He opened at 33/1 and, despite topping early polls on around 20%, the star of "The Apprentice" remained easy to back around [15.0] throughout the summer of 2015.
Fellow outsider Ben Carson would briefly head him in the polls that summer but Trump proved more resilient than expected. He lost the Iowa Caucus to Ted Cruz and was briefly rivalled at the top of the betting by Marco Rubio. However the following week, Trump would trounce a divided opposition in New Hampshire and rattle an establishment that had never taken him seriously.
A long fight with Cruz - hardly an establishment favourite, either - would ensue and speculation remained rife that he would be usurped at the party convention for months. As it turned out, 'Lyin Ted' refused to endorse Trump but the party establishment came on board. The rest is history.