Boris Johnson is giving his leadership bid one more heave before it is all over

To land the Tory crown, he may need to seize it before March 2019 when the UK leaves the EU

May’s allies suspect Boris was trying to be sacked with his recent outbursts – and insist she was right to deny him martyrdom (Getty)

“Let the lion roar” was the hardly self-effacing title given by Boris Johnson's aides to his speech to the Tory conference on “promoting global Britain” today. It was a reference to Winston Churchill’s remark after the Second World War that: “I was not the lion, but it fell to me to give the lion’s roar.” The Foreign Secretary does not lack ambition.

By the time Johnson’s speech was issued by Tory HQ, it was entitled the more anodyne “winning the future”. He said the lion was not him, but the British people; the politicians should let them roar as the country seized the opportunities of Brexit.

Johnson made a good speech, injecting some fizz into a very flat conference. But the reaction from his audience was more muted than after his barnstormers in recent years. Perhaps Tory members were not fooled by his protestations of loyalty to Theresa May. He said she would deliver “a great Brexit deal based on that Florence speech on whose every syllable, I can tell you, the whole Cabinet is united”.

Boris is back. That was the whole point of his ruthless self-promotion in the past two weeks. He deliberately overstepped the mark – and the rules of cabinet collective responsibility – by setting out his own Brexit agenda in The Daily Telegraph (his article was actually a speech Downing Street told him not to make) and then claiming through allies that it forced Theresa May to dilute her Florence speech (which No 10 hotly denies). He then issued his four Brexit “red lines” in The Sun.

On the eve of his speech, Boris used the oldest trick in the political book and blamed all the fuss on the media. Asked where his “red lines” had come from, Johnson told the BBC’s Newsnight: “Search me Guv!” Disingenuous to say the least. So the media merely imagined his 4,200 words in the Telegraph and his Sun interview? I don’t think so.

The former journalist knew exactly what he was doing. After an invisible summer, and kept out of the Brexit loop by May, he was frustrated and desperate to get back in the limelight. “A child-like cry for attention,” was how one fellow minister described it.

We also know, thanks to an excellent documentary by Channel 4’s Gary Gibbon, that Boris apparently believes May will be gone within a year and that he probably has “one more go at the top job in him and then it’s really over”.

This gets to the heart of the matter. It’s all about Boris’s naked ambition. To land the Tory crown, he may need to seize it before March 2019 when the UK leaves the EU. May wants to see that process through. No one at the conference takes seriously her desire to lead the party into the next election; 2019 is as good as it gets for her. The chatter in Manchester’s crowded bars and restaurants is that the Tories might then want to “turn the page” on Brexit and install a fresh face as leader so they can move on. In which case Johnson’s moment might have passed.

His intervention worked only up to a point. He is back at the top of the “next leader” table, according to a poll of Tory members by the ConservativeHome website. But he is on 21 per cent and A N Other is second on 19 per cent. And Johnson is only in mid-table in the Cabinet performance league.

Many Tory MPs believe Johnson’s posturing has backfired because his disloyalty to May undermined her authority just when she needed to reassert it. “He’s a Marmite figure now – he repels as many people as he attracts,” said one MP. Another described Johnson as “more mouse than lion”.

Although the Tories’ 100,000 members will elect the party’s next leader, a shortlist of two is chosen by its MPs and there would be a determined effort by his enemies to keep Boris off. After his short-lived campaign last year, when he was stabbed in the front by his fellow Leaver Michael Gove, another humiliating setback would spell the end for the blond ambition.

We are not there yet. May’s allies claim his loyal speech means he has backtracked on his Brexit demands and is back in his box. They suspect he wanted her to sack him and insist she was right to deny him martyrdom.

However, Johnson could again hint at resigning over the painful compromises May will soon need to make to keep the EU negotiations on track – a role for the European Court of Justice during the post-2019 transitional phase and beefing up her €20bn (£18bn) divorce payment offer.

Johnson’s friends insist his actions have opened up a debate on the most crucial Brexit question of all – the long-term UK-EU relationship – which May wanted to shut down. Sooner or later, May will have to choose between Philip Hammond’s plan to hug the EU close and the clean break favoured by Johnson. The Boris soap opera is not over yet.