Seawoll nodded, so I gave the full account: our theory that Henry Pyke was a revenant, a vampire ghost bent on revenge who was acting out the traditional story of Punch and Judy using real people as puppets, and that together we had devised a way to put ourselves into the story so that Nightingale could track Henry Pyke’s bones and destroy them. Stephanopoulos couldn’t suppress a wince when I talked about the magical aspects of the case – Seawoll was unreadable. When we got to the shooting he asked me whether I recognised the gunman.

‘No,’ I said. ‘Who is he?’

‘His name is Christopher Pinkman,’ said Seawoll, ‘and he denies that he shot anyone. He claims he was walking home from the opera when two men attacked him in the street.’

‘How does he explain the gun?’ I asked.

‘He claims there wasn’t a gun,’ said Seawoll. ‘He stated that the last thing he remembers was leaving the opera, and the very next thing is being kicked in the head by you.’

‘That and the excruciating pain from the fractured bones in his lower leg,’ said Stephanopoulos. ‘Plus some serious bruising and contusions from when he was thrown to the ground.’

‘Was he tested for gunshot residue?’ I asked.

‘He teaches chemistry at Westminster School,’ said Stephanopoulos.

‘Bugger,’ I said. The gunshot residue test was notoriously unreliable, and if the suspect handled chemicals for a living then no forensic witness on earth was going to testify in court that it was likely, let alone conclusive, that he’d fired a gun. A horrible suspicion formed in my mind.

‘You did find a gun – right?’ I asked.

‘No firearm was recovered from the scene,’ said Stephanopoulos.

‘I kicked it along the pavement,’ I said.

‘No firearm was recovered,’ said Stephanopoulos slowly.

‘I saw it,’ I said. ‘It was a semi-automatic pistol of some sort.’

‘Nothing was found.’

‘Then how did Nightingale get shot?’ I asked.

‘That,’ said Seawoll, ‘is what we were hoping you could tell us.’

‘Are you suggesting I shot him?’

‘Did you?’ asked Stephanopoulos.

My mouth was suddenly dry. ‘No,’ I said. ‘I didn’t shoot him, and if there’s no gun, what am I supposed to have not shot him with?’

‘Apparently you can move things around with your mind,’ said Stephanopoulos.

‘Not with my mind,’ I said.

‘Then how?’ asked Stephanopoulos.

‘With magic,’ I said.

‘Okay, with magic,’ said Stephanopoulos.

‘How fast can you move something?’ said Seawoll.

‘Not as fast as a bullet,’ I said.

‘Really,’ said Stephanopoulos.

‘How fast is that?’

‘Three hundred and fifty metres per second,’ I said. ‘For a modern pistol. Higher for a rifle.’

‘What’s that in old money?’ asked Seawoll.

‘I don’t know,’ I said. ‘But if you lend me a calculator I can work it out.’