He looked down at his sandwich, lifted the top piece of bread and squeezed mustard across the meat and gherkin from a plastic bottle. ‘You can be sure that liver’s kosher?’

‘You know what, Mal,’ she said, with rising irritation at his attitude, ‘so long as it is a match and healthy, I don’t actually care where it comes from. I care about saving my daughter’s life. Sorry,’ she corrected herself, looking at him pointedly, ‘our daughter’s life.’

He put the mustard dispenser down and laid the bread back across the pink beef. Then he picked the sandwich up, opened his jaws, sizing up where to take the first bite, then put it back down on the plate, as if he had suddenly lost his appetite.

‘Shit,’ he said, shaking his head.

‘I know you have other priorities, Mal.’

He shook his head again. ‘Two hundred and fifty-two thousand pounds?’

‘Yes. Well, it’s down to two hundred and twenty-seven thousand since an hour ago. My mother has got twenty-five thousand life savings in a building society account she’s letting me have.’

‘That’s decent. But two hundred and twenty-seven thousand. That’s an impossible sum!’

‘I’m a debt collector. I hear that line twenty times a day. That’s what almost every single one of my clients tells me, Impossible. Impossible. You know what? No sum is impossible, it’s just a question of attitude. There’s always a way. I haven’t come here to listen to you telling me you are going to let Caitlin die because we can’t find a lousy two hundred and fifty-two thousand pounds. I want you to help me find it.’

‘Even if we did find it, what guarantees do we have – you know – that this woman will deliver? That it will work? That we aren’t faced with this same situation in six months’ time?’

‘None,’ she said baldly.

He stared at her in silence.

‘There’s only one guarantee I can give you, Mal. That if I – we – don’t find this money, Caitlin will be dead by Christmas – or soon after.’

His big shoulders went limp suddenly. ‘I have some savings,’ he said. ‘I’ve got just over fifty thousand – I increased my mortgage a couple of years ago, to free up some cash to pay for an extension. But we had planning problems.’ He was about to add that Jane would go nuts if he gave it to Lynn, but he kept quiet about that. ‘I can let you have that if it helps.’

Lynn leapt across the table, almost knocking their drinks over, and kissed him clumsily on the cheek.

Only one hundred and seventy-five thousand to go! she thought.

The fine architectural heritage of the city of Brighton and Hove had long been one of its major attractions, to residents and visitors alike. Although it had been blighted in parts by functional, drab modern buildings, anyone turning a corner in its sprawling downtown and mid-town areas would find themselves in a street, or a twitten, of Georgian, Victorian or Edwardian terraced houses or villas, some in fine condition, others less so.

Silwood Road was a typical such gem that had seen better times. Visitors with an eye for architecture, heading south to the seafront from the bland shopping precinct of Western Road, might choose Silwood Road, then stop and stare, but it wasn’t so much from a sense of visual joy, as shock that such a perfect row of canopied Victorian terraced houses could be in such shabby company.

Shrouded by a forest of estate agency letting signs, it remained steadfastly a downmarket area, not helped by the fact that in recent years it had become part of the city’s discreet red-light district.

At five o’clock in the afternoon, and already pitch dark outside, Bella Moy said to Nick Nicholl, who was driving, ‘Pull over anywhere you can.’

The DC pulled the unmarked grey Ford Focus estate into a parking bay beneath a Resident’s Parking sign and switched off the engine.

‘Ever been to a brothel before?’ she asked.

House of Babes was going to be their first call.

Blushing, he replied, ‘No, I haven’t actually.’

‘They have a unique smell,’ she said.

‘What kind of smell?’

‘You’ll see what I mean. You could blindfold me and I’d know I was in a brothel.’

They climbed out of the car and walked a short distance down the street in the blustery wind, the DC carrying his notebook. Then he followed Bella to the front door of one of the houses and stood, beneath the silent eye of a surveillance camera, patiently waiting as she rang the bell. Bella was dressed in a brown trouser suit that looked one size too big for her and clumsy black shoes.

‘Hello?’ A chirpy woman’s voice, with a Yorkshire accent, came through the intercom.

‘Detective Sergeant Moy and DC Nicholl from Sussex CID.’

There was a sharp rasp from the entryphone buzzer, then a loud click. Bella pushed the door open and Nick followed her in, nostrils twitching, but all that greeted him was a reek of cigarette smoke and takeaway food.

The dingy hallway was lit with a low-wattage red bulb. There was badly worn pink wall-to-wall carpeting and the walls were papered in a magenta flock. On a plasma screen on the wall, a black woman was giving oral sex to a tattooed, muscular white man who had a penis bigger than Nick Nicholl could have ever thought possible.

Then a woman appeared. She was short, in her mid-fifties, dressed in shell-suit trousers and wearing a blouse that revealed an acreage of cleavage. Her face, beneath a fringe of long brown hair, must have been pretty when she was younger and ten stone slimmer, Nick Nicholl thought.

‘DS Moy!’ she said in a little-girl voice. ‘Nice to see you. Always good to see you!’

‘Good evening, Joey. This is my colleague, DC Nick Nicholl,’ Bella replied curtly, a little harshly, Nick thought.

‘Nice to meet you, DC Nicholl,’ she said deferentially. ‘Nice name, Nick. I got a son called Nick, you know!’

‘Ah,’ he said. ‘Right.’

She led them through into a reception area that surprised Nick. He had been expecting to see, from images in books and films, a gilded, mirrored, velour-draped parlour. Instead he was in a tip of a room, with two battered sofas, a cluttered desk on which sat a steaming, opened pot-noodle carton with a plastic fork sticking out of it, an array of grimy-looking mugs and several unemptied ashtrays, overflowing with butts. An old phone sat on the desk, alongside an elderly-looking fax machine. On the wall above he saw a price list.

‘Can I offer either of you a drink? Coffee, tea, Coca-Cola?’ She sat back down, glanced at her pot-noodle meal, but left it steaming, half eaten.

‘No, we’re fine,’ Bella said stiffly, to Nicholl’s relief as he stared again at the grimy mugs.

There was an unwritten understanding between the city’s brothels and the police that, provided those running them did not use under-age or trafficked girls, they were left alone – subject to them allowing random, unannounced inspections from police officers. Most brothel owners and managers, including this woman, respected this, but Bella had learned never to let anyone confuse tolerance with friendship.

She showed the woman, Joey, the three e-fit photographs.

‘Have you seen any of these people before?’

She studied the picture of the dead girl closely, then each of the two boys and shook her head.

‘No, never.’

‘How many girls do you have here this evening?’ Bella asked.

‘Five at the moment.’

‘Any new ones?’

‘Yes, two new arrivals from Europe. A girl called Anca and one called Nusha.’

‘Where are they from?’

‘Romania,’ she said, adding, ‘Bucharest,’ as if trying to show her willingness to be helpful.

‘Are they – um – free?’ said Bella, delicately.

‘I’ve seen their ID,’ the madame said anxiously. ‘Anca’s nineteen, Nusha’s twenty.’

There was a sharp, rasping ring. The woman’s eyes went up to a wall-mounted television monitor. On the poor-quality colour screen they could see a balding, bug-eyed man in a suit and tie.