He looked again at the three young men who had caught his attention earlier. They were deep in serious conversation at the other end of the room. They were still sober, they were lithe and looked keen and clever. Were they up to something? It was just possible . . . He didn’t want any amateurs fouling up his evening. Better be certain. He strolled around the perimeter of the room and edged within earshot of their table. So oblivious of his presence were they, their earnest debate continued without hesitation: a debate on the new backless, double-breasted waistcoats – could one possibly wear these things? Snooty Felbrigg had been seen in one . . . but, on the other hand, Fruity Featherstonehaugh had been heard to declare them ‘flashy’. Armitage was interested enough to linger close by until they delivered their decision – a decided thumbs down.

‘Where are you, Felix?’ he wondered. ‘Not at this table, I think.’

He moved around towards the door, staying on the fringes of the party, confident that the official Ritz security staff uniform he had put on for the occasion would render him invisible. If they noticed him at all, the toffs would be mildly reassured by his presence. But the guests were paying him no more attention than they paid the waiter who served them their consommé en gelée. Apart, that is, from two young girls who had been eyeing him for some minutes now, giggling to each other behind their hands. Both were a little the worse for drink. Drink? The worse for something anyway.

The sergeant gave them his reproving police stare which usually did the trick. He knew that he was a good-looking man and he came in for his share of female appreciation. It wasn’t always unwelcome but he wanted no attention from this pair. Underdressed, in his opinion, for a family do – those wisps of dresses were a plain incitement to crime – and their eyes were too bright. They’d spent quite a long time out of the room – in the ladies’ cloakroom perhaps? – and Armitage’s suspicious mind conjured up activities more often associated with nightclubs. Not Ciro’s, he thought – the Embassy, more like. They said you could get anything at the Embassy. People of this class spent more on an evening’s shot of cocaine than he spent on his week’s rent. His stare grew more deadly.

The girls walked flirtily in front of him, turned and walked back again, passing more closely. The small evening bag one had been carrying suddenly slipped and fell at his feet. Automatically he bent and picked it up. Clicking his heels smartly, he held it out. ‘Excusez-moi, mademoiselle, vous avez laissé tomber ce petit sac.’

Disconcerted, the girl took it from him. ‘Ooh, er, thank you,’ she mumbled.

‘De rien, mademoiselle. De rien.’

Wide-eyed and giggling, the girls scurried back to the flock.

He smiled with satisfaction. It never failed. He could always put people on the wrong footing by addressing them in French or German. The English would run a mile rather than deal face to face with a foreigner. He decided that if anyone else approached him he would give them a burst of Russian. He continued to survey the crowd. The three waistcoat fanciers were still at it and presenting no problems. No, if there was to be any suggestion of disorder arising from this group it was more likely to come from the women.

His eye followed the striking redhead he’d marked down earlier. She stood out from the crowd of flappers and gigglers, distinguished by her height – she towered over most of the men – and by her colouring. Her dark red hair was unfashionably long and piled on top of her head. This had the effect of lengthening further her elegant neck, her elegant neck around which hung a very remarkable necklace. Armitage had lost no time in giving it his professional attention. Emeralds, he judged, and the real goods. A family piece, he guessed, recently and fashionably reset. The stones were large, carried in a simple but heavy gold setting. She had chosen to emphasize their colour by wearing a low-cut gown of dark green taffeta which framed them as they lay gleaming against her smooth white throat.

He indulged for a moment or two in salacious thought. He acknowledged that she was, by his standards, quite old – perhaps even forty – but, given a chance to lay aboard, he wouldn’t have refused. He didn’t think many men would have refused. He watched on as she made her way towards the group of three who had become the focus of his surveillance. Well, at least it simplified things to have all his targets in one shot for a while. He approached the group softly, intrigued to hear their conversation. The woman laughed and flirted and sipped her cocktail prettily. The men vied to exceed each other in gallantry, obviously flattered by her attention. She twirled the stem of her glass and, when one of them noticed it was empty and called to a passing waiter, she asked for ‘Another French Rose. And no sugar round the rim!’ He had not been keeping count but he was aware that she was drinking steadily though you would never have guessed it from her speech or her behaviour. Yes, she could manage her drink, that one.

Now she was moving on to join that rancid toad Sir Montagu Mathurin at his table. There were stories circulating about him that made the sergeant’s flesh crawl and for a split second he was tempted to approach and warn her to move on. But then he pulled himself up. What was he thinking of? The chap was probably her second cousin or something and, anyway, this lady was capable of looking after herself. She greeted Mathurin’s rather sulky-looking little girlfriend (fiancée rather, judging by the ring which was visible clear across the room) with much warmth but at once turned the full glow of her charm on the rogue Mathurin. This was decidedly a display of a sexual nature, Armitage reckoned, frowning anxiously as he watched the apparently casual but practised gesture with which she leaned towards him and adjusted his tie. Anybody could see what that meant! Even across the room the sergeant felt the force of it and he swallowed in sympathy. Certainly Mathurin was responding in a predictable way. It was a relief to see that after a few minutes of fascinating Mathurin she had the good manners to draw the fiancée into the conversation. Trouble averted then. The last thing he wanted was the distraction of a pedigree cat fight but all claws seemed to be sheathed. And this was the Ritz after all, not the London Apprentice. And these were ladies not dockers’ molls.

A clock chimed midnight and this was greeted with raucous calls for more champagne. The redhead rose to her feet and began to thread her way through the crowd towards the door. She paused, turned and directed a look at someone on the other side of the room. Damn! Armitage looked round but he wasn’t quick enough to catch an answering look of complicity from any of the other revellers and wondered cynically which of the assembled men was the chosen one. He wished he had a mate in earshot to take on a bet with him. Whichever bloke rose to his feet and excused himself within the next five minutes, he reckoned was the lucky one. A matronly lady in wine-red brocade staggered to her feet and made her way, listing heavily, towards the door. A pretty girl in a short dress about as concealing as a cobweb noticed her predicament and with a cry of concern hurried after her, steadying her with a hand under an elbow and an encouraging smile. At a look from the maître d’hôtel, a waitress scurried after the pair to check there were no embarrassing scenes in the corridor. A group of chirruping girls followed, flighting their way like finches to the powder room, and Armitage wondered what instinct compelled them to undertake this journey across the room in flocks. Mathurin, deserted for the moment by his fiancée, looked at his watch in anxiety – or was it just boredom? But he stayed in his place. And that was the only excitement. After ten minutes Armitage decided with a sigh of relief that he’d misinterpreted the signals.