Thoughtfully, all murmured something along those lines, raised their glasses and took a very small sip.

Lily’s palms were beginning to sweat with fear. It seemed a cold draught was blowing on the back of her neck. She told herself that the male members of the gathering were not her responsibility. She told herself that a six-foot Serbian sporting a duelling scar and brazenly imposing himself on the company was hardly the elusive Irish woman they were seeking. But the feeling of dread would not leave her. With a surge of relief, she saw the imposing figure of Sandilands passing with a full plate some yards away. She screwed up her courage and called out to him.

‘Joe! What ho, Joe!’

He spun around, concerned, alerted by the intimate use of his name.

Almost crushed by the sudden attention she was attracting, she managed an encouraging: ‘Won’t you come and join us?’

He stood surveying the group until Rupert took over, inviting him to sit next to the Serbian in the remaining place. He introduced Sandilands to his neighbour.

‘You’ve just missed an amazing tale of derring-do,’ Edward commented.

‘Oh, yes!’ Lily added. ‘A chapter from John Buchan, you’d swear! Do you realize you’re sitting next to an assassin, Joe?’ Her voice sounded improbably girlish to her own ears but Sandilands’ presence was giving her confidence and she knew he was receiving her message. ‘A self-confessed assassin! An expert in poisoning, shooting, clubbing and drowning.’

‘Great heavens! Your Highness is not, I trust, about to demonstrate any of these skills this evening? Perhaps someone should tell him whom he’s sitting next to?’ Sandilands said calmly, shaking out his napkin.

‘A Scotland Yard detective, I understand?’ Gustavus nodded. ‘But off duty tonight, I’m presuming? No cause for concern on either side. I perform no lethal tricks where there are ladies present.’

‘And, speaking of ladies – where is your own beautiful new wife?’

‘You are acquainted with Zinia?’

‘No, I haven’t yet had the honour, but I read the society pages of the Tatler,’ Joe said happily. ‘May we expect her to join us?’ He leaned towards Lily and remarked: ‘I think you’d admire her, Lily. I hear she is a dark-haired beauty with a profile to give Cleopatra a run for her money. I’ve been looking out for her all evening without a single sighting.’

‘Zinia has retreated to the powder room to perform some small task – she caught the hem of her dress on a heel, I believe.’

Lily tried not to jump to her feet too eagerly. ‘But she’s missing the fun! I shall go and find her. Perhaps I can be of assistance. I’m a jolly good needlewoman … though there’s usually a woman in attendance down there with needle and thread.’ She tilted her head to the guests and made off before anyone could call her back, glad to escape the demands of her assumed role for a few minutes.

The prince – her prince – was surely safe enough guarded by Sandilands and Rupert. But what of the assas-sin’s wife? Was she another weapon in Gustavus’s armoury? Lily reversed her thinking. Was Gustavus a weapon in the armoury of the mysterious dark lady skulking down below away from public view? Lily didn’t believe she’d caught sight of any such woman since she’d entered the hotel. Could anyone possibly be hiding in the cloakroom all this time? Ladies’ cloakrooms, she remembered from her briefing, were her responsibility. Sandilands would expect her to take action.

Lily found there were two vast and ornate powder rooms in the basement. She was directed away from the farther one by the attendant, who seemed, Lily thought, rather distraught.

‘Can you help me?’ Lily asked her. ‘I’m looking for a friend of mine who came down here some time ago. She’s having problems with the hem of her dress.’

The attendant’s relief was instant. ‘Oh, thank goodness someone’s come for her. She’s in a right state. I’ve offered her assistance but she just screams and yells at me to leave her in peace. I didn’t know who to call for. She’s commandeered a whole room for herself. What am I meant to do, miss, when the after-supper surge comes down? She’s in there.’

Lily went through the padded door into a lavender-scented space lit by discreet electric light bulbs. ‘Zinia? Are you there?’

Her only answer was a stifled snuffle and ‘Didn’t I tell you to go away?’ from the armchair placed in one corner for swooning ladies who needed to take the weight off their feet. Lily approached, watchful and prepared for action, though the pitiful bundle curled in the depths of the chair seemed to offer no challenge.

‘Hello. My name’s Lily Wentworth. I hear you could do with some help with your dress.’ As there was no reply she added: ‘I was just talking to your husband upstairs. He’s wondering when you’re going to re-join him at the party.’

A howl of anger greeted this offering. A flood of Russian – oaths by the sound of it – and then: ‘Never! Swine! Evil, loathsome man! I’m sitting here trying to get up the courage to find a back way out of this place. I shall walk away and never see him again.’

‘Seems a bit drastic. Do you have somewhere to flee to? Always a good idea to have an exit strategy.’ Lily’s tone was exaggeratedly light.

‘I’d rather sleep on the streets than next to him. I’d rather sleep in the zoo! In the reptile cage!’ The vehemence of the replies was not abating. This display of overheating rage was the last thing Lily wanted to encounter. Any woman with the bad luck to be married to Gustavus deserved her sympathy, but something had to be done to deflate this swelling emotion.

‘May I ask you to stand up, madam, put your hands on your head and turn round slowly?’ Lily asked abruptly in a police voice.

‘I beg your pardon? Why on earth should I? Who are you to ask such a thing?’ The girl was sufficiently startled to raise her head and stop sobbing.

‘I’ll answer both questions when you’ve done as I ask.’

‘Oh, very well! Strange English ways! One is obliged to humour one’s hosts, I suppose.’ Zinia sighed, stood up, lifted her arms and turned around.

‘A beauty,’ Sandilands had said. It was difficult to see loveliness in a face that was wrecked by tears that had channelled through her powder and smudged her lip rouge. Mascara was no more than large black smudges under her eyes. And yet the features had the strange attractiveness of a pug dog’s squashed face. The eyes were large, dark and lustrous, the nose straight and short above an upper lip that was slightly too long for perfection. The mouth below was well shaped, but over generous in Lily’s estimation. Lily was reassured to see that the girl was shorter than herself and very slightly built. And it was clear that, in her clinging silk, Zinia was not concealing a weapon.

‘Thank you – just making quite sure you’re not carrying a pistol.’

‘A pistol?’ The astonishment could not have been faked. ‘Why would I be carrying a pistol?’

‘Wife of a self-confessed assassin – one can’t be too careful,’ Lily said lightly.

‘Assassin!’ The word was spat out in disgust. ‘He was never closer than a hundred miles to Rasputin, if that’s the yarn he’s been spinning. And ask yourself this – what sort of man has to brag about being a killer to get the admiration of the crowd?’

‘Soldiers sometimes do,’ Lily said equably. ‘And your husband would appear to be every inch the soldier. The military bearing … the scar—’

‘Pouf! The scar was incised by a surgeon’s scalpel in Vienna. Under anaesthetic. False. Like everything about the man. He is an … impostor.’

‘That’s a very melodramatic word. I beg your pardon. This is all a bit hard for me to understand. Listen, Zinia, and I’ll spell out my concerns. Your husband was just a few minutes ago introduced to the heir to the British throne, in whose company I find myself this evening … Gustavus is even now sitting at the Prince of Wales’s table. Surely—’