‘Quite! I’d be looking at you a long time before a cart horse came to mind, miss! No — what I’ve got my sights on is a hunter. Light bay with an intelligent eye. Shows courage over fences. Ideally one that doesn’t bite your hand off down to the arm-pit when you offer it a sugar lump.’

At last she’d smiled at him. He returned her smile and forged on. ‘Now — a further test. The lout you sat upon at Paddington … the Sparrowhawk. Had you been in charge of the case instead of Inspector Proudfoot, how would you have proceeded with him?’

She nodded and sat forward in her chair, understanding that her interview had, at last, got under way. She spoke up with confidence. ‘I’d have located his headquarters and raided it.’

‘Easily said — but if he refused to reveal its whereabouts? And I have to tell you — he did refuse. Rather forcefully. Hard man under that foppish exterior.’

‘I would have assumed so. But there were other indications. The flowers were freshly bought and the florist whose wrapper was still around them might have something to tell. But, for speed, I’d have consulted the one reliable witness we already had at the scene. The witness who would have led us straight to his base of operations. I’d have just followed the dog, sir. Let it lead me to its home, which would most probably have been a shortish distance away — I’m guessing somewhere north of the park, along the Bayswater Road. Then I’d have mounted a raid.’

‘Good. Good.’ He nodded. ‘Proudfoot — and the dog — got there in the end.’

‘And the little girl and her brother?’

‘Are safely lodged with the aunt they’d set out to find in London. She lives out east in one of those streets between Petticoat Lane and Spitalfields … they’d never have found her under their own steam. The poor woman! She’d no idea they even existed, so it must have been quite a shock when the NSPCC knocked on her door. But she rallied round quite admirably, they report, and took them in. And what a Dickensian scene I imagine that to have been! They were runaways from a particularly distressing situation in their home village. Brave little pair. They’ll come through.’ Something in her expression made him add: ‘And yes, I shall be checking on their well-being.’

He slid a file across his desk at her. She’d passed the first two of his four tests. Physically: perfect. Under nine stone, less than five foot seven and attractive. Intellectually: astute. But what sort of a strategist was she? He needed a girl who could think for herself, and fast. He’d decided which fence to put her at.

‘And now we come to it … the reason I summoned you here. Your first case, Wentworth. Disturbing, urgent and of national importance. I want you to acquaint yourself with the contents of this file, which must not leave my office. When you’ve read it-’