‘Sort of thing you can’t imagine happening outside of a book!’

With a shaking hand the Colonel lit his cigar, then added, ‘D**n it all, Evadne, it could be one of yours!’

‘Hah!’ snorted the lady in question, straightening her pince-nez, which were sitting askew on the bridge of her nose. ‘That only proves what I suspected all along.’

‘What d’you mean?’

‘That you were fibbing when you told me how much you enjoyed my stuff.’

‘Fibbing? Well, of all the –’

‘If you’d actually read my novels, Roger ffolkes, instead of just pretending to have read them, you’d know I never touch locked rooms. I leave them to John Dickson Carr.’

The Colonel was patently calculating how best to bluster his way out of the fix he’d got himself into when his daughter Selina, who until that instant had been seated beside her mother on the sofa, her face buried in her hands, suddenly startled both of them by shouting, ‘Oh, for God’s sake stop it, you two! You’re being absolutely horrid, behaving just as though we were playing a game of Murder! Ray is lying dead’ – she made a histrionic gesture in the vague direction of the attic – ‘shot through the heart! Don’t you even care!’

These last four words were spoken in audible capital letters: DON’T YOU EVEN CARE! It’s true that, when Selina decided to study art instead of going on the stage, she may have chosen the wrong calling, but on this occasion nobody could have doubted her sincerity. She had only just ceased sobbing, all of half-an-hour after the body had been discovered. And though he and his wife had done what they could to comfort her, the Colonel, in the heat and confusion of that discovery, had already forgotten the strength of his daughter’s feelings for the victim. He was now wearing a rather sheepish expression on his ruddycomplexioned features.

‘Sorry, my sweet, sorry. I’m being awfully callous. It’s just – well, it’s just that this murder is so extraordinary I still haven’t got over it!’ He put an arm round her shoulder. ‘Forgive me, forgive me.’

Then, typically, his mind started wandering again.

‘Never known a locked-room murder to happen in real life,’ he muttered to himself. ‘Might be worth writing to The Times.’

‘Ohhh, father!’

While the Colonel’s wife continued ineffectually to pat her daughter on the knees, Donald, the American boy Selina had met at art school, hovered solicitously over her. He was, though, too bashful to do what he was surely pining to do, which was to cradle her in his arms. (That’s Donald Duckworth, by the way, an unfortunate name, but his parents couldn’t have anticipated that when they christened him back in 1915.)

In truth, the Colonel was by no means the sole offender. Though it’s fair to say everybody present sympathised with Selina, some vocally, some silently, there could be no getting around the fact that, of the house-party, only she truly mourned the dead man. Even if their minds hadn’t been monopolised by the astounding trappings of the crime, the others, without exception, had their own individual reasons for not wasting too much time in formulating conventional expressions of regret over the departure from this world of Raymond Gentry. Nobody, in short, was prepared to shed crocodile tears, and only Selina ffolkes real ones.

So if, on that Boxing Day morning, an intruder were to have strayed into the wood-panelled drawing-room of ffolkes Manor – its ineradicably male aura, as pungent as the aroma of one of the Colonel’s cigars, feminised by a row of delicate Royal Doulton figurines on the mantelpiece and the exquisite petit-point that covered the armchairs – he would certainly have sensed a pervasive atmosphere of shock and even fear. But he would also have been puzzled by the virtual absence of personal grief.

The grandfather clock had just struck quarter-past seven. The huddled servants were already in their uniforms, while the guests were still in their dressing-gowns – except, that is, for Cora Rutherford, the stage and screen actress, one of Mary ffolkes’s oldest friends. She was wearing a gaudy purple-and-gold garment which she called a ‘kimono’ and claimed was a Paris ‘exclusive’. And it was she who spoke next.

‘Why doesn’t one of you men do something?’

The Colonel looked up sharply.

‘Take a hold on yourself, Cora,’ he cautioned her. ‘This is no time to go wobbly.’

‘Oh, for heaven’s sake, Roger, you silly man!’ she replied in her habitual tone of cordial contempt. ‘My nerves are of stronger steel than yours.’

As though to demonstrate, she took a slim shagreen cigarette-case from one of her kimono pockets, drew out a cigarette, inserted it into an elongated ebony holder, lit it and dragged the smoke deep into her lungs, all with fingers as steady as the Colonel’s had been shaky.

‘All I meant,’ she went on calmly, ‘was that we just can’t sit here with a dead body directly over our heads. We’ve got to take action.’

‘Yes, but what?’ answered the Colonel. ‘Farrar has tried the ’phone – how many times, Farrar?’

‘About half-a-dozen, sir.’

‘Right. The lines are down and they’re probably going to stay down for some while to come. And as you can perfectly well hear for yourself, the blizzard that brought them down is still raging outside. We have to face the facts. We’re snowed in. Completely cut off – at least until this storm blows itself out. The nearest police station is more than thirty miles away and the only road that leads to it must be impassable.’

With a furtive glance at Selina, he concluded:

‘And, after all, it’s not as though – well, I mean to say, our Christmas get-together is utterly ruined and all that, and it’s extremely unpleasant for all of us, but it’s not as though the body’s about to – about to walk away. I’m afraid we’re just going to have to sit it out for as long as it takes.’

It was then that, from the fireside armchair in which she was ensconced, snug and shapeless in her woollen dressing-gown, Evadne Mount, the novelist we’ve already been introduced to, said to the Colonel with a hint of urgency in her mannish voice, ‘You know, Roger, I wonder if we can actually afford to do that.’

‘Do what?’

‘Sit it out, as you say.’

The Colonel shot her a quizzical look.

‘And why not?’

‘Well, let’s just consider what has happened here. Half-an-hour ago the body of Raymond Gentry was found dead in the attic. You, Roger, had to break down the door to get to him, a door that was locked on the inside with its key still in the keyhole. As if that weren’t enough, the room’s one and only window was barred. So, to all intents and purposes, nobody could have entered the attic – yet somebody did – and, once inside, who knows how, nobody could have got back out again – yet there’s no denying that somebody also succeeded in doing just that.

‘Now, as I’ve already told you, Roger, I don’t do locked-room murders. I’ve written nine novels and three plays – my latest, The Wrong Voice, is in its fourth triumphant year in the West End as we speak – beat that, Agatha Christie! – and not one of them has featured a murder committed inside a locked room. So I can’t pretend to have the foggiest notion how this murder was done.

‘But,’ she went on, pausing for a second or two, clearly holding back so that her next statement would have the greatest possible effect on her listeners, ‘I do know who did it.’

And, indeed, the effect was devastating. The drawing-room went deathly quiet. A few seconds elapsed when time seemed suspended. The servants stopped their nervous shuffling. Cora Rutherford’s immaculately manicured fingers stopped dancing a pirouette on the transparent rim of her glass ashtray. Even the grandfather clock stopped ticking – or else tick-tocked on tiptoe.

The silence was finally, bathetically, brought to an end by an eruption of nasal wailing from the butter-fingered kitchen-maid Adelaide, adenoidal Addie, the other maids called her, who would burst into tears at the drop of a hat – or at least of a china teacup. With a loud ‘Wheeesht, girl!’, however, Mrs Varley, the cook, put an end to that, and everybody turned again to face Evadne Mount.

It was the Colonel who posed the inevitable question.

‘Oh, you do, do you? So tell us. Who did it?’

‘One of us.’

Strangely, none of the indignant protestations she might have assumed would follow such a dramatic assertion were forthcoming. On the contrary, it was as though its logic had impressed everybody, instantly and simultaneously, as irrefutable.

‘I know that this house is situated right on the edge of Dartmoor,’ she continued, ‘and probably fantasies of escaped convicts have been flitting through all of your brains. And, yes, it’s true that, with the ’phone lines down, we can’t know for sure that some escaped convict isn’t roaming about the countryside. As far as I’m concerned, though, it’s not on. Like the White Queen, I’m capable of believing as many as six impossible things before breakfast – well, let’s say after breakfast,’ she corrected herself, ‘I’m nothing till I’ve had my coffee. And, as an avid reader of my dear friend John Dickson Carr’s whodunits, I’m also capable of believing that somebody managed to materialise then dematerialise inside that locked attic room, killing Raymond Gentry in the meantime, and all...