John heard a hiss of breath at the unending, irresistible grandeur and folly of the man, and realised it was cold air through his own teeth. The king swore that he died in the faith of his father, as a Christian, and then spoke quietly to the executioner.

‘Oh God, don’t let him botch it,’ John whispered, thinking not of the executioner who had done this a hundred times, but of the king who must do this beautifully, just once.

The king turned to Bishop Juxon and the bishop helped him to tuck his long hair under his cap to keep his neck free for the blade. Charles handed his George and the ribbon of the Garter to the bishop, and pulled the ring from his finger.

‘No, not that, no, no,’ John muttered. The details were unbearable. John had nerved himself for an execution; not for a man undressing as if in domestic confidence, tucking his hair out of the way of his pale, fragile neck. ‘Oh please God, no.’

Charles took off his doublet but wrapped his cloak around his shoulders again, as if it mattered that he should not catch cold. He seemed to be complaining about the executioner’s block. The executioner, a terrifying figure in his masquing disguise, seemed to be apologising. John, remembering the king’s ability to delay and prevaricate, found that he was shaking the fence post before him in painful impatience.

The king stepped back and looked up at the sky, his hands raised. John heard the scribble of a pencil behind him as a sketch-maker captured the image of the king, the martyr of the people, his eyes on heaven, his arms outspread like a statue of Christ. Then the king dropped his cloak, knelt down before the block and stretched out his neck.

The executioner had to wait for the signal; the king had to spread out his arms to consent. For a while he knelt there, unmoving. The executioner leaned forwards and moved a wisp of hair. He waited.

‘Please, do it,’ John whispered to his old master. ‘Please, please, just do it.’

There was a wait of what seemed like hours, then with the gesture of a man diving into a deep river the king flung his arms out wide and the axe swept a lovely unstoppable arc downwards, thudded into his neck bone, and his head dropped neatly off.

A deep groan came from the crowd – the sound a man makes at his death, the sound a man makes at the height of his pleasure. The sound of something ending, which can never happen again.

At once there were slow, determined hoofbeats behind them and people screaming and pushing in panic to get away.

‘Come on!’ Alexander cried, tugging at John’s sleeve. ‘The cavalry is coming through, out of the way, man, we’ll be ridden down.’