‘I’m not complaining. To be honest, I was glad that you were able to let yourself go like that.’ She held up the letter. ‘While you were getting some long-overdue sleep, I’ve been wrestling with a problem of my own. This is an invitation from the Prince Regent to go to Brighton Pavilion.’

‘What a wonderful honour!’ cried Dorothea.

‘In one sense, it is. In another, I feel that it would make me beholden to him.’

‘But you want to go, surely?’

‘I’m tempted. I’ll admit that.’

‘I’d accept the invitation at once. Everyone says that the Pavilion is like nothing else in this country. How can you even think of turning down His Royal Highness?’ said Dorothea, excitedly. ‘It would be an insult.’

Gilbert Street was a thoroughfare in the more affluent part of Marylebone. He could see that the White Lion was a public house of some distinction. The adjacent house, a detached property of fairly recent construction, had a pleasing symmetry to it. What interested him was that it also had a side gate. He was no longer disguised as a beggar. Having disposed of one of the men ordered to kill him, he felt confident enough to wear his usual apparel. He walked on past the house, then, having reached the end of the road, he waited ten minutes before strolling past it again on the opposite pavement. His reconnaissance was complete.

Thanks to his brother, Peter had some idea what to expect when he called on Hugh Denley. He was a tall, spare, agitated man in his fifties with a bulbous forehead and a wispy beard. Though a servant allowed Peter to step into the hall, he got no further. Denley came out to see who his visitor was.

‘What are you doing here, Mr Skillen?’ he asked, inhospitably. ‘I’ve told you all that I’m prepared to say. You may as well leave at once.’

‘Before I do that,’ said Peter, ‘there’s something you should know. The person you talked to earlier was my twin brother, Paul. He was grateful that you felt able to be so frank with him. When reviewing his notes of the conversation, however, he felt that there were one or two gaps. I’m here in the hope of filling them.’

‘Then you’re going to be disappointed.’

‘Don’t be too rash, sir.’

Denley opened the front door again. ‘Goodbye, Mr Skillen.’

‘If you turn me away, I’ll feel duty-bound to pass on your name to the Bow Street Runners. Their questioning won’t be half as respectful as ours. For a start, they’ll insist that you’re hauled before the chief magistrate and then,’ Peter went on with a cautionary smile, ‘there’s the small matter of your illegal duel.’

‘There’s no need for them to know anything about that.’