‘Indeed! Thank you, constable. Leave it on the table, would you?’

Sandilands opened the envelope and spent some moments inspecting the contents. ‘As good as police efforts,’ he commented. ‘No — better. We’ll start by reminding ourselves of the evening’s work — here’s a photograph of the POW at the start of the proceedings, safely in the arms of the Met.’ He paused for a moment, studying the print. ‘Goodness me! Whatever were you doing with him, Wentworth?’

‘A waltz, sir,’ Lily confirmed as Cyril’s deliberately glamorous photograph circulated to astonished stares from the CID men.

‘And he survives to waltz another day — let’s keep that in mind. And here’s a useful shot of the company at the table before the event.’ He paused, absorbed by the next subject. ‘Followed by a society pose showing our victim — scarred cheek, shifty grin — in the close and apparently friendly company of the POW.’

Rupert shuddered. ‘We should have picked him up and marched him straight out, sir. We sat there and watched.’

‘Your anxiety is shared, Fanshawe. But remember Gustavus was there at the Prince of Wales’s invitation. Let’s not indulge in unwarranted breast-beating; we were reacting to the social demands of the situation. This is not a police state. Our role is to advise and protect. We do not pick up and march out a gentleman who has been invited to seat himself at the prince’s table. We had both arrived at the same assessment: that there was no threat to the Prince of Wales’s well-being. Gustavus was unarmed. He’d been searched. He was surrounded by security officers — one false move and he’d have been rendered harmless. And he knew that. Rather tormented us with his heavy-footed humour on that score. He was revelling in the attention, you’d say. And enjoying cosying up to the prince.’

‘Sir!’ Lily spoke swiftly. ‘Again, his wife has an explanation. No sinister political motive involved — she claimed that he was seeking proximity for purposes of social aggrandizement. He just wanted his photo in the press … posing with the prince, on the front page of the society journals.’

Rupert groaned. ‘They will do it! I’ll make that steward account for the bulge in his back pocket.’

Sandilands nodded and carried on. ‘Now here’s a view of the table as it was at the moment Prince Gustavus sank gargling from view on the far side. The plates and glasses — I want you to consider them. The contents have been bagged and bottled and are at present at the lab undergoing the usual tests. Rupert — take us through it.’

‘The far side, where you see a half-full glass of wine, was the POW’s place. Next to him, on his right hand, where you see an empty glass, was the place Miss Wentworth had originally occupied. In her absence, Gustavus, finding the effort of shouting in Serbian from his original place over the table too demanding, had sidled round, taking his glass with him, and plonked himself in Wentworth’s vacated seat. He had previously turned down offers to have food fetched but had consumed a quantity of wine.’