I had nothing with me but the clothes I was wearing: blue jeans, hooded sweatshirt, black windbreaker. Phone, wallet, keys. That was it. It felt like I’d forgotten something: a bag, a backpack, a child, a pushchair, something to hold on to. When I travelled, when I went anywhere, there was always something in one hand or the other. Or both. Travelling totally unencumbered had always been an appealing thought but today it felt weird, like it wasn’t me. Like something vital was missing.

It was 5.40 p.m. William’s teatime would be finished and Mel would be getting ready to run his bath, wash his hair, then he’d have his story and ask for a second. A surge of homesickness hit me, raw and powerful, and I thought for a moment that this journey was a terrible mistake. This was wrong. My place wasn’t here on a train leaving them behind, my place was at home with my family.

You won’t have a family life if you get sent to prison. You won’t have a family life if you don’t find Ben before the police find you.

The die was cast, the decision taken. It was too late to change it now.

I thought about ringing Naylor, sharing my suspicions that Ben was either on his way to Sunderland or was already there now. But was there enough evidence for Naylor to take it seriously? I wasn’t sure: it was instinct and intuition and educated guesswork based on a handful of clues that Ben had left behind. It was for me to do this. Alone.

And besides, I had to get answers to my own questions before the police charged me with a murder I hadn’t committed. A murder that hadn’t even happened.

It was four hours to Sunderland. Time to kill. I got an over-brewed coffee from the buffet trolley, put two milks and three sugars in it, and went onto Facebook. Trawled through all of Ben’s posts from the last few weeks again, looking at the profiles of the people he commented on most frequently, checking dates, times, content. Somewhere there would be a clue that could put me in a room with him. Help to end this madness. I just knew it.