They’d scouted the area and established it was possible to reach the van without being spotted by Rob. Pushing through the undergrowth on the other side of the fence, they could observe the caravan called Strawberry, secluded at the far end of the pitches, a cream building with a pitched roof, a set of steps leading to a front door and overhang porch; in brief, it was a house on a raised platform, and it was that platform the team were looking at.

Murray had spied movement inside the van and was certain he’d glimpsed Fabia. He ran through their plan one more time.

‘Lucy and I will make a dash for it and squeeze under the van, see if we can establish where they all are inside,’ said Murray. ‘Once the diversion is in place, it will give us time to separate them and take appropriate action.’

Ian gave him a look, ‘With all due respect, mate, you can barely see through those peepers of yours. You were having trouble when we were driving here. You might not be able to pick up on any peripheral movement and could be in danger. I’ll go.’

‘You trying to brown nose again?’ asked Murray, bristling.

Ian shook his head seriously. ‘No, I’m trying to save you from getting hurt or worse.’

Murray looked him up and down through swollen lids and tipped him a grateful nod. ‘Fair enough. You’re a skinny runt. You’ll slide under the van more easily than me anyway. Natalie?’

Natalie agreed. ‘You can be part of the diversion, Murray. It makes more sense.’

Lucy’s phone vibrated in her pocket. She answered it. ‘Ten minutes,’ she said to the others.

Natalie’s face was serious. ‘Okay… go!’

Lucy shot up the fence like a professional climber, fingers and toes finding spaces in the wire with ease. She landed effortlessly on the other side, raced towards the van and threw herself underneath it, crawling to the far side where they knew the sitting room to be. She rolled onto her back, chest rising and falling quickly, straining for sounds above her. Ian, more ungainly but equally quick, pursued her and launched himself onto the ground, rolled over three times and reached the near side of the van, where he remained transfixed, head facing her.

‘Anything?’ she mouthed.

He gave the thumbs down.

There were footsteps above her and then a voice, a man’s voice. It was Rob, his words surprisingly clear.

‘I didn’t burn it because I wanted you to hear it all, be the recipient of what I’ve been harbouring all the time you’ve been happily growing up and enjoying family life. This is what I have had to live with. You wanted to know what was in the letter, so here it is. I hope you’re sitting comfortably. Please try not to interrupt or analyse me. It would be very much the wrong thing to do.’

Ian hissed Lucy’s name quietly and pointed above him to the bedroom. ‘Philippe – crying.’

Lucy whispered into the comms unit, ‘Child, bedroom one. Vic and perp, lounge.’

‘Copy.’

In the sitting room, Rob was monologuing. ‘Why did you leave me, Mother? Why couldn’t you love me enough to take me with you? Do you have any idea of the emotions that tore me apart daily as a consequence of your actions? Why?

‘Who convinced you to desert me? Who whispered in your ear that it was right to desert your son? Who, Mother, who?

‘Where did you go? Was it better than our home? Of course it was. You hated the claustrophobic hell-hole as much as I did, yet you allowed me to continue suffering and found somewhere far more agreeable for yourself. Where did you hide, Mother?

‘What did I do so wrong you had to leave me behind? Was I so awful you had to leave me with a man who didn’t care whether I lived or died, who either ignored me or beat me, who hated the very sight of me, because every time he looked at me, it reminded him that you had abandoned us both? What did I do wrong, Mother?

‘I love you. I hate you. Love you. Hate you. The constant seesaw of emotions is exhausting. One day I crave to see you. The next, I wish you were a rotting carcass. Bitch!

‘I have never lived. My life has been nothing but a desire to seek you out and to ask you these questions. It has been a life filled with bewilderment, desperate hope and pain, and one that has had no meaning. I have not been able to form any relationships with others, because who can I trust? If my own flesh and blood deserted me, then what might a stranger do to me? Besides, I have nothing left to give. Every ounce of love was for you.

‘When I was little I used to dream you would return, carry me away with you and hold me to your heart. As I grew into a teenager, I loathed you and that anger turned inwards and twisted and deformed my development. How could I grow and mature when my need for you held me back? As an adult, I found the solution: Look for you. Find you. Take back what was lost.

‘Which brings me onto this letter. I found you, Mother. After many fruitless years, I hired an excellent private detective who tracked you down and told me the horrible truth. You had left my father and me for another man, turned your back on us both and walked away without a word of explanation so you could start afresh, have a new family, a sparkling, happy new family.

‘Were they better than me, Mother? Was it easier to bring up two girls than your little boy, who you couldn’t bear to touch or hold? Did you have endless joy playing with them and holding their hands as you walked home from school with them? Did you pour all your love into them and mould them and pray for them and have hopes for them?

‘You can’t shake off the past, Mother. It comes back to haunt you. My hatred has been brewing for many years and the nightmares that haunted me gave me the idea to murder not only you but those you love. It’s taken skilful planning and endless time to hone my skill, unfortunate women who reminded me of you – the same hair, the same eyes and the same beautiful expression when they look at their children – have been sacrificed in preparation for this task.

‘Now I am ready. By the time you learn of this letter and its contents, you will know what it feels like to lose that part of you that is joined to your own being, the very essence of you that makes you human. Your children will be dust, and you too will be desperate to experience ever-lasting oblivion.

‘So, Mother, I do this out of love and out of hate for you.

‘Your son. The one you left behind.

‘Rob.’

Lucy winced. The man was deranged. Her comms unit crackled softly, and she heard the whispered command: ‘Decoy. Prepare.’ Lucy glanced across at Ian and nodded then watched the wheels of the wheelchair being pushed in the direction of the sitting room window and recognised the boots of the supposed orderly behind the handlebars. She strained to hear what was happening above her. Timing was crucial.

Rob was talking again. ‘What do you think, Doctor? Reckon she’ll shed as many tears as I have over the years? Of course, she won’t actually be able to read the letter – or rather, like you, listen to it – until I’ve got rid of you and your sister. It’ll take a while before I reach the endgame, but I’m a patient man, and by the time I read it out loud again, I’ll have turned my attention to her and she’ll be eager for death. What the fuck? What’s he doing here?’

Footsteps rang above Lucy’s head and she turned onto her belly, ready to take action. Ian copied her movements. The front door swung open and Rob exited, standing on the top step. ‘What the hell are you doing here? Haven’t you died yet?’

He stepped down, his Gucci loafers and white socks now visible. One more step and she’d be able to act. He descended another step and another swiftly, all the while volleying abuse at his father. Lucy’s hands shot forward and, grabbing him by the ankles, she tugged with all her might, felling him. Ian bounded from his cover and hurled himself at Rob. Murray thundered across from his position behind the wheelchair and a scuffle ensued. Lucy held on tightly. Events unfolded at speed: a flash of steel, a yell, Murray’s boot in Rob’s face, and more flashing as the blade swung left and right towards Murray, Ian launching himself in front of Murray, a scream of pain, another boot, and Murray on top of Rob, yanking the man’s arms behind him and cuffing him in one swift movement. Rob didn’t move. His feet went limp. Ian slumped to the ground. Blood turned the grass crimson.

‘Bloody hell! You okay, mate?’ Murray’s voice was pure concern.

Lucy scrambled out from under the van and raced to Ian’s side. Natalie hurtled towards them alongside a couple of officers. Lucy examined the wound and pressed hard on it with the flat of her hand. ‘Ambulance!’ she yelled.

Natalie barked instructions to the officers and halted at the foot of the stairs, taking in the scene.

‘I’ve got this,’ said Lucy, pushing her hand hard against Ian’s shoulder to stem the flow. ‘Go check on them.’

Natalie’s chin dipped once and she tore up the stairs into the caravan. Fabia was tied to a chair with duct tape, her face blank with shock. Natalie pulled away the piece covering her mouth.

‘Are you all right?’ Natalie asked.

‘Yes. Philippe?’

The boy’s terrified cries were loud.

Natalie followed them and rattled the bedroom door. It was secured but the key was in the lock and she turned it. The toddler stood directly behind the door, tears streaming down his face.

‘Hush, hush. Everything’s okay, now. Your mummy’s here. Let’s go see her.’ Natalie scooped him into her arms and carried him through, speaking softly to him all the while. ‘You stand here next to your mummy. We have to unstick her from the chair. You look after her.’ The boy laid his head in his mother’s lap, thumb in mouth, shoulders shaking as he sobbed silently, while Natalie searched for some scissors and released Fabia from her bounds.

Once her wrists were cut free, Fabia leant over her boy, stroking his head. ‘He’s crazy. He was going to kill us both.’

‘It’s over. You’re safe now. You’re safe,’ Natalie repeated. She glanced through the door at the manic scene outside. Rob’s head was lowered in defeat, his hands cuffed, two officers either side of him, as Murray read him his rights. An emergency medical kit was open on the grass and paramedics busied around Ian, attaching a plasma bag and attending to the knife wound.

‘I have to go outside. Someone will be with you in a minute. Stay here.’

‘I’m not going anywhere,’ said Fabia.

Natalie bounded back down the stairs. Ian’s appearance shocked her. He’d lost a lot of blood and was fading fast, his eyelids fluttering. ‘How bad is it?’

The older of the two paramedics spoke as they worked quickly to stem the blood flow. ‘Bad. We’ll stabilise him and get him to hospital immediately.’

She placed a hand on Ian’s good arm and smiled at him. His eyelids fluttered open briefly. ‘You did great. I’ll be sure to commend you,’ she said. His lips stretched into a smile momentarily before he fell unconscious.

Lucy watched them lift Ian onto a stretcher and waited until they were out of sight before walking across to Donald, now being looked after by a nurse.

‘I appreciate you helping us. It can’t have been easy.’

He pulled the mask away and spoke. ‘Easier than I imagined. Throw the book at him. He’s rotten to the core.’

‘Is it okay if we return to the home now?’ asked the nurse.

Lucy nodded. ‘Thank you, again.’ She placed her hand on the man’s and received a nod in return.