Jeremy Corbyn Vs Owen Smith in final Labour debate: What to expect

Labour leader Jeremy Corbyn and MP Owen Smith are set to go head-to-head in front of a live television audience for the last time tonight as the long and acrimonious party leadership race comes to an end this month.

The event, which will be screened at 9pm tonight on Sky News and moderated by its political editor Faisal Islam, is expected to see questions put to both candidates by Labour members and supporters a week before the ballot closes.

However, the Huffington Post has revealed that Corbyn's team has threatened to withdraw from the debate due to concerns over audience balance. The pollster Survation is carrying out checks to ensure the audience is evenly split, but the Labour leader's allies say there is potential "conflict of interest".

"[They] suspect that Survation is doing polling work for the Smith campaign," the website reports. "Both Sky News and Survation have offered assurances [that this is not the case] but the Corbyn camp are demanding more clarity."

"It's 50-50 at the moment as to whether we will take part," one of the leader's allies said. "We are still making the decision. There is still cause for concern and we don't want to find out after the programme that we were proved right."

There has been no official confirmation from team Corbyn that a withdrawal from the debate is being considered, but the Labour leader has previously pulled out of hustings due to accusations of bias.

Many political commentators say Corbyn has had the upper hand throughout the leadership contest.

"As incumbent, Corbyn gets to be optimistic about Labour's current situation," says the New Statesmen. The Labour leader is likely to once again cite by-election wins, mayoral elections and several Tory U-turns.

As the challenger to the status quo, it falls to Smith to highlight the party's failings, the magazine adds. "From Ukip to Trident, he [is] the voice of – depending on who you ask – reason or cynicism."

The previous debate between the two contenders saw them clash over Brexit, party unity and anti-Semitism, with pundits split on who came out on top.

The recent boundary changes, which is expected to hit Labour the hardest and threaten the Islington MP's parliamentary seat, are likely to feature in the hour-long debate.

The Labour leader remains ahead in both the opinion polls and the betting odds , but the party as a whole is suffering its worst ever opinion poll ratings in opposition. The winner will be announced at a special conference in Liverpool on 24 September. 

Writing in The Guardian on the anniversary of Corbyn's first year in office yesterday, shadow chief secretary to the Treasury Rebecca Long-Bailey said that regardless of the outcome of the debate and contest, the party needs to move forward "in the spirit of optimism, determination and, above all, unity".

 The Battle for Labour airs on Sky News on Wednesday 14 September at 8pm