A murmured question at the other end of the line prompted the response: ‘Oh, yes, I think so. In any case she’ll have to do … no time to look further. She’s the right age — which is to say a year or two younger than our friend. How old is he these days? Twenty-eight?

‘No, she’s not out of the top drawer, I’m afraid. The lowest grade for intake recommended by Sir Nevil — what was it? Upper shop-assistant level? Yes, pitch it there. Is that where you’d find millinery? Hats? But her behaviour’s acceptable. She’ll pass.’

He listened impatiently to a further query and answered briskly: ‘Well of course we have. But none of them has the other qualities we require. My cousin Margery might oblige, if I asked her … though she runs Girl Guides shindigs on Saturday nights, I believe. And I very much doubt she can do the tango.’

He eased the receiver a little way from his ear. ‘Well, there you are then. You’ll have to take what’s on offer. It’s a question of settling for the best balance. I’ve passed them all in review and you’ll have to take my word for it, this is the best we can do. Look — I took the precaution of trailing her before a friend … Lady Dedham … Cassandra. Knowing nothing to the contrary, she took her for one of our upper-class young ladies. In fact, the girl made a very favourable impression. No awkwardness at all, sympathetic and chatty, was the verdict. Cassandra’s asked to see her again — quite unprompted by me. “Someone I can really talk to,” she says. And Cassandra Dedham’s no one’s fool.

‘Accent? Do you know, I hadn’t noticed one,’ Joe lied cheerily. ‘They can always talk to each other in cockney, I suppose … he’s an adept. I’ve heard him at it. And she is a London lass. Though Margery, who seems to have got somewhat fond of the girl, assures me she can, in fact, produce a Mayfair drawl that’s indistinguishable from the real thing. Ghastly, but it might be useful.’

The voice at the other end guffawed and exclaimed: ‘So that was her! Thought it must have been. Did you realize, sir? She rang us up from your office, pretending to be the operator. She got Howard — who’s not the sharpest — and pulled the wool over his eyes. It was a beat or two before he caught on. He thinks he got away with it — played the silly ass and burbled a bit. Told her he was the War Office! That must have shaken her.’

‘Mmm … not so’s you’d notice,’ Joe murmured. ‘I wondered if she’d have the initiative to follow that through. Well, well! I chalk one up to Wentworth. Another one. She seems to be scoring all round the wicket.’

He listened to a further question and replied testily: ‘Educated? Gracious, man — does it matter? She’s hardly likely to be taking part in a Platonic symposium in the company we have in mind. But if you need to know — according to her notes, she matriculated from a boys’ grammar school. Odd, that …’ He consulted his file. ‘Is that possible? Should have been followed up at interview … Not to be dismissed, those establishments … my best super is a product of one such. We’ll probably find they’ve taught her to conjugate a deponent verb and debunk the Phlogiston Theory in a hundred words. Let’s pray she’s not minded to do either on Saturday week. It would fall a bit flat.

‘Appearance? Again, acceptable. No, I’d go so far as to say attractive.’ He cleared his throat and admitted: ‘In fact, damned attractive. Hard to tell what’s under all that serge, of course. I had to use my imagination. Physical type is right — pony rather than the usual shire horse we have on our books. Well coupled up. Moves nicely. A grace that’s natural, you’d say, rather than imposed by deportment classes. Fair hair, fashionably cut. I have to say they’ll make a lovely pair.’

A further muttered question raised a blustering response. ‘Good Lord, man, I didn’t ask. I say — there is a limit!

‘Oh, yes, she has physical courage. Saw her damn nearly get herself knifed at Paddington. Excellent report in her file from her ju-jitsu instructor. And she’s resourceful. I’ll bear witness to both qualities. And, in Margery’s words, she’s “forthcoming”. By that my cousin meant the girl’s ready to speak up for herself.’ Joe grinned. ‘Some might say impertinent and undisciplined. No idea when to hold her tongue. Still, I keep reminding myself — and I remind you, James — it’s not a doormat we’re looking for. And perhaps we shall just have to accommodate and learn to manage a little female free-thinking. I’m ahead of you there — brought up by a suffragist mother and sister, I’ve been doing it all my life. But we have one problem, James, old man. When I said a moment ago that she’d left, I meant exactly that.’ He gave a shout of laughter. ‘So freely does the constable think, she’s just buggered off, leaving me with her resignation letter on my desk.

‘Yes! Yes! Flounced out! I didn’t know whether to have her arrested or give her a round of applause …

‘No, no need for the heavy hand. Not yet. I had the forethought to set a reserve bait. I think I’ve worked out what makes Miss Wentworth tick. She’ll be back in the net before you can say knife. No need for concern. I have our girl in hand. I think we can say with some confidence that it’s all on for Saturday week.’

He looked at his watch. ‘Now, James, I want you and whoever you’ve put in charge of next Saturday’s jollification … Rupert? Ah, yes — good man … to come up here to the ops room for a briefing and exchange of information and to meet your opposite number in the CID, Superintendent Hopkirk. Six suit you? Time we all shook the cards from our sleeves and laid them out on the table. Officers possibly in the line of fire — always a concern whether they’re male, doubly so when they’re female. And “Carnage at Claridges” is not a headline I want to see splashed across the Daily Mirror the next day.’