It's the first Boris Johnson speech that I can remember watching that didn't have any jokes. For his allies, that was the point. It wasn't designed, they say, to make a personal attack on Theresa May.
But my goodness, it made a pretty savage attack on her policies - a "fog of self-doubt", "pretending to the electorate", "a fantastical Heath Robinson" proposal on customs, "miserable permanent limbo".
For someone who less than a fortnight ago celebrated collective cabinet responsibility at Chequers, that's quite some feat.
But it makes me wonder exactly what was being said on the Chequers terrace when we captured Mr Johnson and Mrs May in what looked like vigorous conversation 10 days ago.
What the speech today was designed to do, his supporters hope, was to present the former foreign secretary without the wisecracks, as a serious politician who is determined to argue for what he believes. His now small band of supporters circled him on the green benches as he spoke.
He made the case for the Prime Minister's first big Brexit plan, her speech at Lancaster House back in January 2017 when she first outlined some of her aims and explicitly, completely and totally ruled out staying in the single market.
For some Brexiteers Mr Johnson's words will be hugely welcome, a call to stop the rot as they would see it.
One former minister told me plainly "he was right - Lancaster House is a distant memory", even comparing Mr Johnson's words to the closing scene of Gladiator when Russell Crowe playing the former all powerful Roman General Maximus, bloodied and staggering, said, "there was a dream that was Rome that shall be realized".
The message, one man's dream can inspire a great many others to glory. Forget for a moment it didn't exactly end well for that particular Roman.
But the question this afternoon is whether the speech can start the process of restoring Boris Johnson to his former political glory and more importantly of course, will it make a blind bit of difference to Brexit.
On the first point, as Mr Johnson sat down along with some cheers, I heard another MP though call, "is that it?" His many critics will point to what was not in the speech, a new plan for Brexit.
A government minister told me it was more of his "deluded fantasy" saying his "simplistic notions" about what could be achieved when we leave the EU won't compensate for what we could lose.
Another MP told me "it didn't really go anywhere, it had no substance". The other crucial difference in pushing for the Lancaster House model is that it ignores the not inconsiderable fact that that speech and that set of proposals was developed before the general election, before Theresa May shot herself in the foot.
Mr Johnson however will, after today's speech, be a well-known, prominent voice who has made it plain he will fight against the prime minister's current stance and any attempts to compromise further.
With the turmoil in the Tory party, having him on the loose could, in time, make a difference. Not least, he is one of the few politicians in the country who is known, for good or for ill, by his first name. That is as much of a risk as an asset but it's real, and those who supported Brexit may well listen.
For him, today was not about intentionally blasting into a leadership race, but trying to rebuild a new, for the want of a better word, brand of Boris Johnson.
The clownish caricature that saw him through much of his time as Mayor of London and the referendum didn't wash as foreign secretary.
After that, the number of MPs he excites as a potential leader is tiny these days. But today's speech was not an immediate call but a pitch to get him back in the long term game.
It seems unlikely right now after the last couple of years. But one of his detractors grudgingly admitted "he's never quite the busted flush".