And so, in echoes of Margaret Thatcher, he fights on as all around the government falls apart. Ministers are deserting the sinking ship.
At PMQs, he turned in a performance that raised defiance and stubbornness to the ambit of high principle. All around him his cabinet colleagues sat glumly. Surely they don’t believe he can survive?
Sir Keir Starmer, the Labour leader, decided he would kill with ridicule. He made important points about supporting the victims of unwanted sexual advances and talked of the need for trust and integrity at the heart of government.
His best lines, however, were his most contemptuous and, as he delivered them, Boris Johnson sat looking somewhat bemused and forlorn.
Starmer chided that this was the first recorded case of a sinking ship fleeing the rats. The Labour benches roared their approval and the Tories sat glumly.
He was not finished as he described the “dying acts of his political career” before describing the Prime Minister’s colleagues as the “charge of the lightweight brigade”. He eyed the government frontbench, describing them as a “Z-list cast of nodding dogs”.
Given the chaos of the last 24 hours, it would have been understandable if the Prime Minister looked a broken man. He didn’t, but then again he is a showman and this was the routine when you are deep in a trench and your colleagues are trying to bury you.
His ability not to relate to anything approximating to reality is quite breathtaking. His hubris appears to know no bounds.
On Monday, I wrote that when the Cabinet moves against you the game is up. He must know this, not even this Prime Minister could have lost the plot to the extent to believe he can ride this out.
‘Enough is enough’
I expect more resignations and this story to continue tonight and tomorrow and then into next week if he clings on. Tory MPs are now considering what the influential 1922 Committee can do to put this injured beast of a politician out of his misery.
David Davis called on him to put the national interest above self-interest. He got nowhere with his plea for high politics.
And then Sajid Javid, who quit as health secretary last night, made his resignation statement which was couched in terms that were more in sorrow than anger.
He deplored the fact that he had walked the tightrope between loyalty and integrity too often and had repeatedly given Boris Johnson the benefit of the doubt, only to find the PM wanting, time and again.
He told a hushed House that there is only so many times that you can press the reset button before telling colleagues “enough is enough”.
The problem with this government, said Javid, started at the top and it wasn´t going to change. It was therefore time to change the Prime Minister.
All the while, Boris Johsnon sat stony-faced, trying desperately not to give away his thoughts. He must be thinking though, ‘how long can I go on?’.
This is one of the most dramatic departures from Downing Street I have witnessed.
Different aspects of the EU debate claimed the premierships of both David Cameron and Theresa May.
Gordon Brown lost an election, as did John Major. Tony Blair succumbed to internal speculation about his future.
The clear parallel here is with Margaret Thatcher. Although it was a policy (the poll tax) which greased her path to resignation, it was her stubbornness and inability to meet reality even halfway that produced a Cabinet revolt of sorts.
Ministers continue to quit and they will join the ranks of the malcontents and those who are already plotting his downfall.
‘Ceased to be’
Boris Johnson is like that famous Monty Python parrot. He has ceased to be.
Rarely can the expression ‘in office but not in power’ be so apt to describe what we have at the moment.
They don’t do it this way in banana republics, they really don’t.