Time for Boris Johnson to show the nation what he’s made of - Andrew Vine

How enlightening it will be I can only guess, but there is at least a chance that the members of the public asked to put questions to the candidates by the debate’s presenter, Emily Maitlis, might land a punch or two that rocks them back on their heels.

Let’s hope so, because we need some honesty and reality. All we’ve had from them is carefully-choreographed posturing and vapid generalisations that give no real indication of where Britain heads under their leadership or how the mess that Brexit has become is to be resolved.

Even Sunday night’s debate on Channel 4 – ducked by the front-runner, Boris Johnson – produced more heat than light, with the candidates apparently convinced that squabbling equates to statesmanlike behaviour.

Maybe tonight, having consented to appear, the darling of so many Conservatives will produce some justification for his long-held belief that destiny points him towards Downing Street. But I’m not counting on it, because between them the candidates have effectively created a policy-free zone at a point in Britain’s history when the country needs clear direction.

It’s not just on Brexit, but on all the other pressing problems, such as the grossly unfair treatment of the North, social care or the crisis in local government funding. Spin and soundbites are all that have been offered, and if a member of the Great British public kicks a hole through that façade to let some daylight in on whatever lies behind, they’ll deserve the cheer that goes up in my house and in probably a lot of others as well.

But if that does happen, it might reveal a lack of ideas, because what this leadership contest has demonstrated is that the candidates are essentially singing the same old songs about Brexit that we’ve heard for the past three years – and it’s a broken record.

The familiar refrains are all there – the EU will back down under the threat of a no-deal departure, we won’t honour the legally-binding agreement to pay £39bn, countries are lining up to do trade deals with Britain, the impasse over the border with Ireland can be magically resolved.

There is absolutely nothing new in any of this, and the candidates are conveniently choosing to ignore that.

Nor does anything said hold out much hope of breaking the Parliamentary deadlock that ultimately finished Theresa May, apart from the outrageous suggestion of suspending the session to deny MPs a say on any deal, which if it was attempted ought to cause uproar amongst the electorate.

So we’re left with poses being struck and platitudes offered, aimed at pressing the buttons of the Conservative membership who will make the decision.

Vague guff about wanting the best for Britain and seeing the country do well simply doesn’t cut the mustard. There isn’t an MP in Parliament who doesn’t want those things.

There has to be more than that, a detailed set of proposals to end the ghastly drift and damage the country has suffered since 2016, and to somehow start a process of reconciliation amongst a divided people. Are any of them really up to that? We might get an indication of that tonight, but then again it may be dispiriting to watch, because each in his way has played a part in the failures.

There is still more than a month to go before Conservative members decide on behalf of the rest of us who leads the country, but it’s already clear that barring an unexpected scandal suddenly blowing up, one of the final two candidates will be Boris Johnson.

That’s guaranteed by the numbers of Tory MPs who backed him last week, even before today’s further whittling-down of the number of candidates in advance of tonight’s debate. It’s to be hoped that the viewers asking questions tonight home in on Mr Johnson, whose hitherto voracious appetite for publicity and voicing his opinions has been strangely absent. The launch of his leadership campaign looked meticulously rehearsed, as if the candidate had been taken in hand by a theatre director and given a role to portray, with every gesture, facial expression and nuance of voice stage-managed to the minutest detail.

Gaffes were not part of the script, but tonight, live and with the agenda set by the questions of voters that might be a different matter. The familiar bluster and ruffling of hair won’t really work in this context. There needs to be something more beyond easy generalities – substance and detail. What does he really believe in, beyond the personal ambitions of Boris Johnson? If, as is looking increasingly likely, we will sit down to watch the Prime Minister-in-waiting give his first address to the nation, he needs to tell us.