‘Hold fast,’ Tradescant replied. ‘We are early. It’s only the poor people who have been sleeping at the quayside and around the city who will have known when we were sighted. The king himself could arrive at any moment.’

Someone shouted a curse from the quayside and Buckingham turned his bright smile towards them as if it were a hurrah.

‘He could,’ he agreed levelly. ‘He could.’

‘There! Look! cried John. ‘A coach, my lord! They have sent a coach for you!’

Buckingham turned quickly and squinted down the quayside into the bright autumn sunshine. For a heart-stopping moment they could not see the livery of the coach. It could have been a royal warrant to arrest him. But then Buckingham’s laugh rang out.

‘By God, it is the royal coach! I am to be met with honour!’

It was unmistakable. Buckingham himself had introduced the fashion for six-horse carriages into England and only he and the king used them. Two postillions in royal livery jogged on the two leading pairs of horses, the coachman sat in scarlet and gold on the box, a footman beside him, and two liveried footmen clung to the rear. The horses had plumes of scarlet in their bridles, their hooves rang on the cobbles. The king’s flags were on the four corners of the coach. The royal herald was inside.

Buckingham ran like a boy to the head of the gangplank to see this bright guarantee of his continuing wealth and power trotting towards him. Behind it came another coach with a crest on the door, and another. Behind that came another coach, and a marching band playing whistles and drums. Two heralds carried Buckingham’s flag. The coach stopped at the gangplank and they let down the steps for the royal herald. Behind him from the second coach came Kate, Buckingham’s wife, and his redoubtable mother the Papist countess.

Buckingham strode to the head of the gangplank to greet them, his head tilted, his smile quizzical. John followed, a pace behind him. The herald marched up the gangplank and dropped to his knee.

‘My lord duke, you are welcome home,’ the man said. ‘The king sends you greetings and bids you to come to him at once. The court is at Whitehall. And he bids me give you this.’

He produced a purse. Buckingham, with a slight smile, opened it. A bracelet heavy with enormous diamonds spilled out into his cupped hands. ‘This is a pretty gift,’ he said equably.

‘I have private messages for you, from His Majesty,’ the herald added. ‘And he bids you use his coach for your journey to him.’