But we had all seen what secrets did to people, even to the very best of friends. Even to a friendship that had endured for half a lifetime. The secret that now bound Jennifer and me together had also torn us apart. I had been thinking about that a lot, since returning from France, about secrets, and lies, and taking responsibility for what we’ve done. About the ghosts that follow us, the damage we leave behind.

About justice.

I thought about that now as I sat in my car, on a suburban street in Ealing.

In one way I was grateful to her for sending me the reminder email, because it helped to make the situation perfectly clear, in case I had been in any doubt: safety for Lucy meant justice denied for Izzy, for Alex Bayley. It meant this one careless comment would be hanging over my daughter forever, with the power to wreck her brilliant future, even though she was not the one who had got behind the wheel of the car.

It meant lying – for the rest of our lives.

Unless I took the initiative.

Jennifer had made her choice. She had been willing to sacrifice anything – even my son’s life – to protect her own children. She had shown me the way.

Now it was my turn to make a choice.

A true and loyal friend.

Two people were dead, their lives snuffed out. And if we allowed their deaths to go unpunished, we were all as good as lost. Their loved ones deserved to know why: the truth, the whole truth, and nothing but the truth.

Most of it, anyway.

Izzy’s family deserved justice. Alex Bayley’s family too.

And as I now knew, sometimes justice needed a helping hand.

*

Checking up and down the street one last time, I got out of my car into the morning drizzle. Heart beating wildly in my chest, I opened my umbrella and held it low over my head as I walked up the short drive to the house, through the side gate to the garden and the back door. I carried a clipboard and a shoulder bag, with a lanyard around my neck, in a trouser suit with a white blouse plus clear-lens glasses. To the casual observer I was just another anonymous charity fundraiser knocking on doors and generally making a nuisance of myself. Worse still, a local councillor looking for votes or a Jehovah’s Witness giving away copies of The Watchtower. All to be avoided, if possible.

The house backed onto a railway line and was not overlooked by the neighbours on either side. From my pocket, I pulled on a pair of disposable latex gloves and plastic covers for my shoes.

No traces. No fingerprints.