‘I didn’t like to interrupt,’ said Donna.

‘I’ll wait here till you get back.’ I crossed my arms.

‘There’s no point.’ Sam jumped out of the driver’s door and grabbed his pack. ‘I’m not going to jump through hoops to convince you to be with me. Oh, crap. The bloody signs are missing. He could be anywhere.’

I gazed out at the forbidding maroon-brick buildings. There were probably twenty stairwells in those blocks and none you would have wanted to walk around without the company of a large bodyguard.

Donna shrugged her way into her jacket. ‘The last time I came here – heart attack – it took four tries to find the right block, and that gate was locked. We had to find a caretaker to unlock it before we could bring in the mobile unit. By the time I made it to the right flat the patient was dead.’

‘Two gang shootings here last month.’

‘You want me to call in a police escort?’ said Donna.

‘No. No time.’

It was eerily quiet, even though it was barely eight p.m. These were estates in a part of the city where only a few years ago children might have been playing out on bikes, sneaking cigarettes and catcalling long into the evening. Now residents double-locked their doors long before dark, and windows were braced with decorative metal bars. Half the sodium lights had been shot out, and the odd remaining one flickered intermittently, as if uncertain whether it was safe to shine.

Sam and Donna, now outside the cab, were talking, their voices lowered. Donna opened the passenger door, reached in and handed me a high-visibility jacket. ‘Right. Put that on and come with us. He doesn’t feel safe leaving you here.’

‘Why couldn’t he –’

‘Oh, you two! For God’s sake! Look, I’m going to head this way, you follow him that way. Okay?’

I stared at her.

‘Sort it out afterwards.’ She strode off, her walkie-talkie buzzing in her hand.

I followed close behind Sam as we went along one length of concrete walkway, then another.

‘Savernake House,’ he muttered. ‘How the hell are we supposed to know which one is Savernake?’ The radio hissed. ‘Control, can we have some guidance? No signs on these buildings, and no idea where this patient is.’

‘Sorry,’ the voice said apologetically. ‘Our map doesn’t show individual block names.’

‘Want me to head off that way?’ I said, pointing in front of us. ‘Then we’ll have three walkways covered. I’ve got my phone with me.’ We halted in a stairwell that reeked of urine and the stale fat of old takeaway cartons. The walkways sat in shadow, only the occasional muffled burble of a television behind the windows suggesting life deep within each small flat. I had expected a distant commotion, some vibration in the air that would lead us to the injured. But this was eerily still.

‘No. Stay close, okay?’

I saw that having me there was making him nervous. I wondered whether I should just leave, but I didn’t want to find my way out by myself.

Sam stopped at the end of the walkway. He turned, shaking his head, his mouth compressed. Donna’s voice crackled across the radio: ‘Nothing this end.’ And then we heard a shout.

‘There,’ I said, following the sound. On the other side of the square, in the half-light, we saw a crouching figure, a body on the ground under the sodium lights.

‘Here we go,’ said Sam, and we started to run.

Speed was everything in his job, he had once told me. It was one of the first things paramedics were taught – the difference a few seconds could make to someone’s chances of survival. If the patient was bleeding out, had had a stroke or a heart attack, it could be those critical few seconds that kept them alive. We bolted along the concrete walkways, down the reeking, dingy stairs, and then we were across the worn grass towards the prostrate figure.

Donna was already down beside her.

‘A girl.’ Sam dropped his pack. ‘I’m sure they said it was a man.’

As Donna checked her for injuries, he called into Control.

‘Yup. Young male, late teens, Afro-Caribbean appearance,’ the dispatcher responded.

Sam clicked off his radio. ‘They must have misheard. It’s like bloody Chinese whispers some days.’

She was about sixteen, her hair neatly braided, her limbs sprawled as if she had recently fallen. She was strangely peaceful. I wondered, fleetingly, if that was how I had looked when he’d found me.

‘Can you hear me, sweetheart?’

She didn’t move. He checked her pupils, her pulse, her airways. She was breathing, and there was no obvious sign of injury. Yet she seemed completely non-responsive. He checked all around her a second time, staring at his equipment.

‘Is she alive?’

Sam’s eyes met Donna’s. He straightened up and glanced around him, thinking. He gazed up at the windows of the estate. They stared down at us like blank, unfriendly eyes. Then he motioned us over and spoke quietly. ‘Something’s not right. Look, I’m going to do the drop-hand test. And when I do, I want you to head for the rig and start the engine. If it’s what I think it is we need to get out of here.’

‘Drugs ambush?’ muttered Donna, her gaze sliding behind me.

‘Might be. Or turf-related. We should have had a Location Match. I’m sure this is where Andy Gibson had that shooting.’

I tried to keep my voice calm. ‘What’s the drop-hand test?’

‘I’m going to lift her hand and drop it from above her face. If she’s acting, she’ll move her hand rather than hit her own face. They always do. It’s like a reflex. But if there’s someone watching, I don’t want them to get wind that we’ve worked it out. Louisa, you act like you’re going to get some more equipment, okay? I’ll do it once you’ve texted me to say you’re at the rig. If anyone’s near it, don’t go in. Just turn round and come straight back to me. Donna, get your pack together, and ready. You go after her. If they see two of us leaving together they’ll know.’

He handed me the keys. I picked up a bag, as if it were mine, and started to walk briskly towards the ambulance. I was suddenly conscious of unseen people watching from the shadows; my heartbeat was thumping in my ears. I tried to make my face expressionless, my movements purposeful.

The walk along the echoing concourse felt achingly long. When I reached the ambulance, I let out a sigh of relief. I reached for the keys, opened the door, and as I stepped up, a voice called from the shadows, ‘Miss.’ I glanced behind me. Nothing. ‘Miss.’