‘Then the crunch came?’ Roy Grace suggested.

‘Exactly. Raj’s company had hit the Financial Regulator’s radar. Raj’s buddy in the Met made a phone call to tell him to get his house in order, PDQ. It was a deliberate breach of the Data Protection Act, providing information that should not have been disclosed. He may well have also perverted the course of justice.’

‘And?’ Grace quizzed.

‘As a result of this call, Raj was able to take preventative action to reduce the evidence that would be recovered by the Met when they raided his home and business premises. That tip-off, Raj told me, probably halved his prison sentence. He’s expecting a future visit from the Met Financial Crimes Team to find out what more he can say about his former clients – he wants to use his information as a bargaining chip to try to get moved from Lewes to an open prison in the Birmingham area to be closer to his family.’

‘So, do you want to confirm this Met detective’s name?’ Grace said.

Guy Batchelor grinned again. ‘It’s as you deduced, Sherlock – or rather, Cleo did. Her maiden name’s not Watson by any chance?’ He opened the notebook on the table and began to read, stumbling at times as he tried to decipher his own handwriting – a problem Roy Grace had often encountered himself, as a junior officer, taking statements in the days before they had become mostly electronic.

When Batchelor had finished, Roy had to restrain himself from punching the air with elation.

Stockbrokers routinely recorded all phone conversations with clients, as proof of any instructions should the client dispute one. Guy Batchelor had just read out the details of a digital recording of Cassian Pewe, pleading with Raj to wipe all records of him making stock purchases and sales over the previous three years before the investigation. Apparently Raj left the evidence with a family member before being imprisoned.

If the real recording was anything close to what Raj had apparently recited to Guy, this was dynamite.

Roy Grace said nothing for a short while, thinking it through. Then he said, ‘There’s one thing I don’t understand, Guy – which is why you’re telling me this?’

Batchelor shrugged. ‘Two reasons, boss. One’s personal, the other isn’t. Personal first. I sent a request to ACC Pewe, asking if he would appear as a character witness at my trial, and he never responded. I sent the request three times.’ He shrugged again. ‘Second reason is I know how much he fucked you around. You always stood by me. I remember your words in court, despite all I’d put you through. I didn’t deserve it, but I’ll respect you forever for it.’

‘Can you do me a favour, Guy? Keep this information confidential for the moment. I’d like to take it directly to Alison Vosper – she’s now a Deputy Assistant Commissioner in the Met. At the time Pewe appears to have committed these crimes he was a serving Metropolitan Police officer. Will you do that?’