AMIDST the blue-on-blue exchanges of the five would-be prime ministers, the Tory elephant in the TV studio was, of course, one Alexander Boris de Pfeffel Johnson.

Jeremy Hunt was the one who simply could not resist pointing out the obvious. “Where is Boris?” he asked, adding: “If his team won't allow him out with five fairly friendly colleagues, how is he going to deal with 27 European countries?" The audience applauded.

During the 2017 General Election, Theresa May learnt to her cost that absenting yourself when everyone else turns up is not a good look. Indeed, the Greens’ Caroline Lucas delivered one of the zingers of the campaign when, asked what was the first quality of leadership, replied: “Turning up.”

Mr Johnson has calculated the fewer times he exposes himself, politically, the more chance he has of wearing the Conservative crown come July 22. But the public are not stupid and nor are Tory Party members.

Boris must realise judgement is the paramount quality in a leader, followed closely by courage.

Not surprisingly the sharp end of the Channel Four live debate came on Brexit.

Mr Stewart once again proved that he is different from his colleagues, whom he berated for their “machismo” and inability to realise a no-deal was not possible because Parliament would block it.

Indeed, the Aid Secretary came up with an amusing metaphor, telling his rivals how he had tried recently to stuff three bin bags in a bin that was full. He tried the “believe in the bin bag” approach but it simply did not work. The bin continued to be full.

The sharpest clash of the debate came when Dominic Raab once again refused to rule out shutting down Parliament to ensure MPs could not block Brexit. This was “unconstitutional,” declared Mr Stewart, while Sajid Javid, the Home Secretary, insisted the party was not selecting a “dictator” and you did not deliver democracy by “trashing democracy”. Strong stuff.

It was interesting to see how Michael Gove appeared to be the most forceful, declaring how he had “won” Brexit by dint of his leadership of the Leave campaign and that of all the candidates Jeremy Corbyn feared him the most.

Mr Hunt, meanwhile, came across as the most benign but warned his urbane manner belied a stubborn streak.

Yet the one who appeared to impress the audience most, in terms of their applause, was Mr Stewart, who, counter-intuitively, said in this polarised political world of Brexit, the energy lay in the “centre ground, in pragmatism, in compromise”.

Brave, perhaps. But, unfortunately, for him this is not where the energy lies when it comes to the Tory membership, who happen to be the electorate.

His fortunes are rising because the Scot comes across as the more thoughtful and personable among the candidates. But on Brexit, they are unlikely to rise enough for him to beat Mr Johnson.

As we all know by now the only person who can beat Boris is Boris himself.

So, again, not surprisingly, Mr Johnson will absent himself today when Lobby journalists in the House of Commons grill his five colleagues.

This, of course, is less important than the visuals of voters seeing a lectern behind which Boris should have stood. In this instance, discretion is certainly not the better part of valour.