‘I thought the bloody trains had stopped running by now,’ Lars whispers. ‘I’ll hold on for the coordinates.’

Carrot and I are already on the helicopter, headsets on, as more information begins to come in. Four carriages of the London train have derailed twenty miles north of Brighton.

‘It’s big,’ Carrot says.

Can I do this?

‘You’re ready,’ he says, answering my unspoken question.

Lars climbs into the front, pulls on the headphones and Carrot prepares for take-off. ‘They’re struggling to get access. We might be the first to get to some of the carriages.’ He turns round. ‘Talk it through with me.’

‘Primary assessment, triage using the CABCDE checklist. We don’t treat anyone until we’re sure the scene is safe and everyone has been assessed.’

‘It can be bloody hard not to jump in and help, Kerry. But stick to it. It really is the only way to keep control of a major incident.’

From the air, the ground looks so Christmassy: yellow garlands criss-cross wildly, the cars on the motorway and the A roads blinking like fairy lights, blurred by the heavy rain. Carrot’s been flying on instruments, but as we get closer, there’s a cluster of blue lights showing the way.

Not nearly enough people on scene.

Lars and Carrot discuss the safest place to land, so I focus on trying to make sense of what I’m seeing. Whatever has made the train derail, it’s happened in the worst possible place, bordering farmland and several ditches or streams. The rear two carriages look only slightly off-kilter, as though they’ve been indulging in a little mulled wine, and I can see movement down there – walking wounded. But the front two carriages hang down the banks, twisted like a child’s toy train.

The rain is still pouring and most of the emergency vehicles – two fire engines, three ambulances – seem to be stranded at the other end of a field.

We are easily the closest.

Carrot lands and Lars and I prepare to deplane. ‘We stick together, all right, Kerry?’

The adrenaline washes away my nerves. There are tens, maybe hundreds of people who need me. I have been building up to this moment for eleven years.

Maybe all my life.

Chapter 63: Joel

24 December 2017

We’re at my parents’ for one of Mum’s show-off shindigs and the folk band she has hired is about to start.

I am so tired I want to go to my den – alone – and sleep till 2018.

‘All right?’ Liv asks, handing me a glass of sparkling grape juice.

‘Yeah. Don’t think it’ll be a late one, though.’