Stan sensed that it was a pretty face. He was not at all certain that he’d be able to identify number 1555 if he ever saw her out of her uniform. Grey eyes? Green? He’d have guessed grey eyes but – her hair? No idea. He lowered his gaze, embarrassed to be caught staring, and turned his eyes to her boots. They couldn’t be comfortable. Knee-high, laced and made of a heavy leather, they could have been designed for Charlie Chaplin. And yet he’d seen these women take off and fly in them in pursuit of a villain. They’d trip up, kick out, stamp and do their ju-jitsu – anything to get a man down and incapacitated.

‘You have a good view of the platform here, Stan?’

‘I keep an eye open. I watch for kids getting off the train without an adult. They’re always easy to spot. They don’t know which way to turn. Up from the country – most of them can’t read so the signs mean nothing to them. If it looks like there’s going to be real trouble I scoop ’em up and take ’em along to the stationmaster’s office. Good bloke! Family man himself. He calls in Dr Barnardo’s or the NSPCC or the Sisters of the Night. I was a runaway myself, miss,’ he confided. ‘From the north. Years ago. I know the signs. And I can spot the vultures gathering … Like now …’ Stan’s voice rasped with dread. ‘Here they come.’

The words struck chill. Wentworth waited anxiously to hear more. But Stan just nodded, absorbed by the crowd beginning to gather to greet the train. Most of them were clutching a platform ticket in their hands.

‘What do you make of that lot, then?’ he asked.

Unresentful at being challenged by the old soldier, she murmured her way through the individuals and groups. ‘Reading from the left … if they’ll just keep still a minute and let me clock them … Two girls. Under twenty. Maids’ day out clothes. Excited. They’re so alike they must be sisters. Probably here to welcome a third and younger sister up from the country to take up her position as between-stairs maid … Of course, they could be alumnae of the local house of ill repute on a recruitment drive. Aphrodite’s on Park Lane? No, I don’t think so.

‘Moving along we have two ladies. Uniformed nanny and her well-dressed employer. Judging by the small bicycle that the nanny’s holding – a shining brand new one – I’d say they’re waiting for the lady’s seven-year-old son who’s taking a break from his prep school … Sick leave? But a bicycle like that – it’s bait that could lure any child into trouble. In the hands of the wrong adult. How am I getting on, Stan?’

He smiled and nodded his approval of her reasoning.

‘Next along. Young man. Smartly turned out. Straw boater. And spats. Spats in summer? Trying too hard, would you say? He must be waiting for his lady-friend. Yes, look – he’s clutching a bunch of florist-bought flowers in one hand. Hothouse roses. Expensive. And in the other he’s got what would seem to be a grotesquely coiffed poodle on a lead. He’s brought the dog along to meet its mistress. It clearly doesn’t belong to the young gent. It rather hates him, do you see?

‘And then, just arrived, a very well-groomed middle-aged man. Sleek dark hair. What do you bet he smells of Trumper’s best hair oil? Foreign-looking. I think we have a valet waiting for his gentleman. Possibly lives in Mayfair and he’s strolled on to the station at the last moment, every hair in place, to take charge of the hand luggage.

‘And at the end there’s a young man with a clipboard. Military bearing. Bored. Commissionaire’s uniform is that? A flunky of some sort, anyway. He’s been sent out by a London club – the Army and Navy? – to scoop up some doddery old duffer and steer him safely to St James’s.’

And, after a moment: ‘They all seem to have come to collect someone in particular. I can’t say any one of them strikes me as a vulture, Stan.’

‘Not vulture. No, I got that wrong. Those birds hang about in noisy mobs, don’t they? What we’ve got circling today is one silent professional. A sparrowhawk.’ Stan shuddered and glowered at the crowd. ‘That’s what they call them. Miss, you ought to watch out for the—’

His words were cut off by the screech of the approaching train’s whistle, the swoosh of steam and the protest of huge wheels grinding to a halt. Doors slammed, greetings were called out, passengers jumped down from the train. The platform ticket holders surged forward hallooing with varying degrees of eagerness, claiming their people.

Lily ticked them off in her head as they made contact. ‘Well, I got three out of five right, Stan,’ she muttered.

The two maids were suddenly three – peas in a pod, twittering with excitement.

A podgy seven-year-old squealed in delight at the sight of his bicycle and shook off the attentions of his mother and his nanny.

A heavily moustached survivor of some ancient war was helped out of a first-class compartment by two porters. He placed himself with a harrumph of greeting into the hands of the flunky with the clipboard.

But she’d been wrong about the dark-haired ‘valet’. To Lily’s surprise, an elegant young lady teetered up on high heels and flung herself into his arms, instantly elevating him from a role of subservience into a matinee idol. Lily watched their embrace for a moment, enthralled, with a mixture of wonder and envy.

The young man in spats, scanning the platform anxiously, had yet to make contact.

It was Stan who spotted them first.

He pointed and mimed a message above the din. Two children were getting hesitantly out of a third-class carriage. The older one, a girl of about eleven with badly plaited pigtails hanging down her back, turned and helped her brother to jump down on to the platform. Lily noticed, with a stab of pity, that the girl was smiling, trying to make a game of it for the little boy. The pair stood for a moment, reeling back from the assault of the noise, sniffing the warm sooty air like wild creatures. They were poorly dressed: the girl was wearing a grey cardigan with holes in the elbows over a drooping cotton frock, while the boy’s clothes were a size too big for him. Their shoes were fastened with baler twine and worn down to nothing at the heels. They were both very skinny. They were also by themselves.

Lily watched as they tried with a pathetic sense of duty to slam shut the heavy door behind them and failed to move it. They gave up, looked about them to see if their shortcoming had been noted and braced themselves to face a new and probably hostile world. Hand in hand, they stood, each clutching a small parcel done up with string.

They began to shuffle forward with the crowd and the girl suddenly pointed, seeing the sign for the exit and mouthing the word. They moved towards it.

The Sparrowhawk was watching them as closely as Lily. He let them take a dozen paces from the train, checking that no adult was following on behind.

Satisfied that they were alone, he made his move.

He strolled over and spoke to them, doffed his boater to the little girl and bent down to their level, his face wreathed in pleasant smiles. The poodle, trained in its responses, Lily was quite certain, licked the children’s hands and fussed about, wagging its stumpy tail.

Their new friend was in no hurry. He talked, he listened and he did a lot of laughing. He didn’t make the mistake of alarming them by offering to take their precious parcels from them. Finally, he handed the dog’s lead to the little girl and himself took the boy by one hand, his flowers still clutched in the other. A charming group, they set off for the exit.

Clumsy with excitement and dread, Stan grabbed his crutch and came round from behind his stall, growling a warning. ‘There they go. Never seen that one before but he’s a wrong ’un if ever I saw one. A real professional. Are you going to do something? Where’s that useless nincompoop of a police constable?’

He started to hobble forward himself but Lily grabbed his arm and held him back. ‘No! Wait! We have to let them get as far as the barrier. Otherwise, he’ll get off with some excuse about escorting them to the lavatory or the refreshment room. Rules, Stan! Stay back!’