‘They’ll all be in the kitchens baking the blinis and boiling up the borscht,’ said Cyril.

‘Kitchens,’ Joe muttered. ‘Nightmare! Full of instruments, sharp and blunt, and poisons of one sort or another. The waiting and catering staff have all been thoroughly checked. Four of my department are at this moment ladling out the caviar and pouring the champagne.’

‘You only have an invitation to attend if you’re rich and influential — or, in your case, Cyril, happen to be a dab hand with a camera. If you catch sight of a stranger or someone who appears to be out of his or her element, someone who doesn’t appear in Debrett or the Almanach de Gotha — we want you to signal it. If you spot someone who may have Irish roots in the middle of the cosmopolitan mêlée, tell us. That’s all. We’d be … I’d be much relieved if you’d agree to do it, Cyril,’ Lily concluded.

He’d be a hard man who could resist the unemphatic plea in her soft voice, the shining trust in the straight gaze, Joe thought. ‘Behave as you usually do,’ he said shortly. ‘Any pictures and copy must be passed before me before printing. Are you on?’

Cyril eyed him, unimpressed by his curtness. ‘You know, Sandilands old son, you could learn a thing or two about seduction from your little cousin.’ He turned to Lily. ‘I’ll do my best, love. And I promise you absolute discretion. Now — what time’s the kick-off and how do we get there?’

Joe had laid on a staff car and chauffeur for the short journey to Park Lane and as they made their way through the West End crowds he unbent sufficiently to repeat his briefing for Tate’s benefit.

‘The prince has been advised to arrive half an hour after we get there, which is to say at eight o’clock sharp. That’ll give us time to get our eye in. He’ll be surrounded by a phalanx of gorgeous young equerries, all falling over themselves to take a bullet, naturally. But they have this disadvantage — they can’t dance with him. And that’s, we believe, where the danger lies. On the dance floor. When he’s greeted the hostess she’ll bring him over to our table and he’ll be introduced to Lily. Their eyes will meet, they’ll take to the floor and they’ll dance till dawn or however long it takes. Her presence alone — that of a presumed new amour — will be sufficient to keep other females at bay. Anyone attempting to muscle in on the royal attention in such circumstances will immediately announce herself as suspect and will be weeded out. The prince is well aware, of course, of what we expect and will play up to it.’

‘Doesn’t mean he’ll do as you tell him,’ commented Tate. ‘He’s got a streak of cussedness about him. Some call it a sense of fun. It drove his security men mad when he was touring India, they say. Always dashing off into the thick of the crowd at a whim in places where every native has a dagger up his jumper. There were death threats coming in every day but you’d never have known it from his behaviour. Always on show — fair hair shining like a beacon, an easy target for anyone with a Lee-Enfield. Anyone could have cracked his skull on the polo field, pushed him off a rampart, seasoned his curry with something special. The only injury he suffered was a sprained right wrist from all the hand-shaking!’

‘We’re not expecting it to be easy,’ said Joe repressively.

‘Still, your assassin — if she exists — ought to stand out a mile. Forgive me for questioning your information, but it sounds a bit barmy to me. I can see your reasoning — Popplewell, Goring, Lansing, Dedham … who’s next, you must have asked? Probably not Churchill — he’s careful and always well armoured against attack.’