Boris Johnson has an enormous amount of experience of debate, having been President of the Oxford Union. Jeremy Corbyn doesn’t. But that doesn’t mean Johnson is in for an easy ride this evening. 

On paper, Johnson should wipe the floor with Corbyn in a head to head debate. Academically, you have a King’s Scholar at Eton and Classics graduate of Balliol College in Oxford against someone with two Es at A-level and one year of Trade Union studies at North London Polytechnic. Furthermore, Johnson has been involved in debates and debating all his life, whereas Corbyn has tended to rumble from one protest of the persuaded to another rally of the already decided, with very little proof he can persuade people to change their mind unless he throws other peoples’ money them.

However, tonight’s ITV debate at 8pm is just not as simple as that. You are about to see someone with no fixed ideology on anything except that he should be in charge of whatever anything is (Johnson) up against someone with firm beliefs on many issues who actually has little care whether he or someone else is in charge (Corbyn). That certainty can be really rather beguiling, because Corbyn will not be equivocating in his advocacy on certain issues, whereas there will be many issues on which Johnson will mumble and ruffle his hair and not quite explain what he thinks apart from that sorting x or y will ‘get Brexit done and bring the country together’.

But let’s go back even further to the principles of a debate between the party in Government and their challengers. Johnson has tried as much as he can to pretend that any Government that came before him is not his responsibility. He wasn’t in Parliament during the Coalition and he was a peripheral part of Theresa May’s government apart from a lot of silliness both in front of and behind a microphone as Foreign Secretary. It has gone as far as saying the Conservatives will ‘unleash Britain’s potential’, when many would argue it was Tory austerity that ‘leashed’ Britain in the first place.

Corbyn can simply say that under Labour things would be better. He of course will also disown anything Labour did between 1997-2010 in Government, as he rebelled against them 500 times. So he will simply come out with a list of what’s wrong with the country (X), say that Labour will fix them (Y) and the rich are going to pay for it (Z). It is a message that is extremely hard to combat, because most of the country might agree X is bad, but the detail of Y is often controversial (see my post yesterday about free broadband), and Z sounds great but is often not practically possible. But that doesn’t matter, when Corbyn or any Labour shadow cabinet minister does their whole ‘I will solve X with Y and Z will pay’ everyone whoops and hollers and whoever is in the incumbent Government struggles to combat it.

What you will see is two experienced campaigners coming up against each other. Theresa May ran unopposed for PM without a single hustings. Johnson has run for Mayor twice and won in Labour controlled London, and many argue he was the difference in the EU referendum. He go through the televised debates in that referendum with two shows of remarkable restraint and clarity with his message, so he can put on a show if he has to. Corbyn has campaigned on things all his life, and has two victorious leadership campaigns under his belt. His clarity of message is pretty much undoubted too.

So, how does Johnson win? Details.

Whilst he will have plenty of pre-prepared laugh lines and jibes at Corbyn, the real key would be to do a public thought experiment on Corbyn of ‘what if you actually had to deliver these things’. Demand to know the cost on an almost itemised basis, demand to know how he would get hold of the tax Corbyn says he can get, demand to know how Corbyn plans to combat this or that possible disadvantage with his policy.

Corbyn has it easier. Unless he is completely devoid of a grasp of reality, he knows that the Conservatives are the more likely to win, which restricts Boris Johnson only to promises he knows he can actually deliver. Corbyn doesn’t even need policies (as in realistic ideas), because majority government is impossible for Labour. So he can focus on what stops or reduces the Conservative majority, which, put simply, is that he would stop X by doing Y with Z paying for it.

Will it happen? We’ll see.