Normally wrangles about TV debates go on for weeks before one is agreed. Yet, before the election campaign has even formally started, ITV have announced a TV debate between Jeremy Corbyn and Boris Johnson on November 19th. This’ll be the first election head to heard this country has had.

Agreement on this debate has been reached so fast, as I say in The Sun this morning, because  both Labour and the Tories think they benefit from this one on one format. On the Labour side, they hope that it helps them unite the anti-Tory vote behind Corbyn. While the Tories want a one on one debate because they think the question of who do you want to be Prime Minister—Boris Johnson or Jeremy Corbyn—favours them.

During the 2017 campaign, Theresa May lost her lead on this question. But right now, Boris Johnson has a 23 point advantage over Corbyn. If he can maintain anything like this margin, then he’ll still be in Number 10 come Christmas.

Downing Street also think that making this election a forced choice between a Tory government and a Labour one works to their benefit. Polling for Conservative Campaign Headquarters shows that half of voters want the Tories in government in some way, compared to only just over a quarter for Labour.

They calculate that making the election a choice between Boris Johnson and Jeremy Corbyn helps them squeeze the Brexit Party vote down, something which is particularly important given Nigel Farage’s determination to put up candidates right across the country.

Influential Tories are also worried that if the Lib Dem leader Jo Swinson turned in a barnstorming performance, her party could begin to threaten the Tories in their shire seats.

The Tories are I understand keen on more than one Corbyn Johnson head to head. However, Johnson himself will not do the seven way debate between the party leaders. The Tories are keen to downplay the importance of this event. I’m told that they are considering sending either Sajid Javid, Michael Gove, Priti Patel or Rishi Sunak as their representative.