They got back to their conversation, she finding in him a sympathetic listener. She liked too the sheer darkness of his skin, and the profuse hair which escaped at the neck and cuffs of his brilliant white shirt. Screw the music, this was looking like it would be a most enjoyable flight.

The purser came on the PA and announced a short delay. ‘Just some security issues groundside, and I’m sure in a couple of minutes we’ll be pushing back and whisking you on your way to the subcontinent.’

This announcement seemed to unsettle her companion, and she lost his attention. Some unusually hurried flight attendant movements along the aisle spoke of something more serious. And then a clunk as the door to the air bridge was reopened. Jet engine sounds intruded, and four burly uniformed officials were led up the aisle by the purser. Susannah’s companion was looking over his shoulder, and stood up just as the first security man approached.

‘Mr Deepak Tripathi? Would you like to come with me, sir?’

He nodded, and then turned to Susannah. ‘Goodbye. It was lovely talking to you. Have a nice flight. It seems I have some pressing business to attend to.’

And she regretted that this was the last she ever saw of him.

By eight p.m. Gillard had formally handed over the nascent Empire of Spice fraud case to the SFO. He had been given an enormous list of documents that the SFO was seeking, few of which Surrey Police possessed. He was told that the shares in Empire of Spice would be suspended first thing tomorrow once the investigation was announced.

In the meantime, he had one last chance to interview Deepak Tripathi locally, before he was handed over to his colleagues in London. Gillard and Shireen took the train back to Teddington, picked up his car and raced off to Heathrow police station. He’d only visited this facility once before, but recalled it was near Terminal Four and, ironically, just a mile or so from Empire of Spice’s Slough headquarters.

The detective guessed that Deepak had committed a series of criminal acts in his misuse of funds at Empire of Spice. What was less certain was what connection this may have had with the murder of Mrs Roy. Circumstantial evidence put him bang in the frame. He was the one close member of the Roy family, at least the only male, who could have been the cyclist who attacked her and close enough to her inner circle to have been the poisoner. What about the motive? Perhaps Mrs Roy had discovered a hole in the accounts, and was being silenced. However Harry Roy’s claim of complete ignorance about the accounting issue was a problem too. Mrs Roy and her son were, by common consent, in contact several times a day, presumably even while he was abroad. If Mrs Roy had discovered a hole in the accounts, the first person to whom she would have turned would undoubtedly have been her son. But he claimed to know nothing about it.