Three or four journalists are clustered around the television, including Lawrie, who is scribbling notes on his pad. For once, I slip in unnoticed. I’m not very good at being on time. Late, I believe those pedantic types call it. I prefer to think of it as running behind schedule.

Lawrie catches my eye and jerks his head towards the screen. I dump my bag on my desk, switch on my computer and join him, morning coffee in hand.

The ITV press office has released another exclusive extract from Thursday’s forthcoming interview. To give credit where it’s due, they’re playing a blinder. The Hilltop House murders have been part of the national news fabric for years, horrifying and fascinating us in equal measure. Dr and Mrs Carter’s extended family have never spoken about the killings. Apart from the trial and the endless newspaper stories discussing what drives a child to kill, the coverage was thin, lacking in facts, mostly gossip and speculation. But this is a genuine scoop. Shannon Carter’s first interview – and she is mesmerizing.

‘That’s tomorrow’s story sorted,’ I say to Lawrie, who is chewing the end of his biro. He’s split the plastic covering and the thin tube inside. His tongue is black from leaking ink.

‘I wish.’ He swipes a hand across his mouth, glum. ‘It’s great stuff, yes, but they’ve put it out too early. You know what Colin’s like. He’ll be bored of it by this afternoon. He’ll want our own exclusive.’

The male interviewer – one of ITV’s most high-profile news presenters – is talking now. He’s all over-whitened teeth and expensive made-to-measure suit, but he’s asking the question that everyone wants an answer to, so I forgive him his trespasses.

‘Your parents were viciously murdered, stabbed in cold blood, twenty-one years ago. What’s changed? Why have you decided to speak about it now?’

‘Money,’ calls out one of the feature writers – Lucy Rosewell, I think – and everybody laughs.

But Shannon Carter can’t hear the derision in the newsroom. She’s locked behind a glass screen. She lifts her shoulders, slides her eyes away from the camera. ‘I need to accept some responsibility for what happened. I have so many regrets.’ She takes a deep breath. ‘Obviously, this has coloured my whole life and, as I get older, I want to try and put it behind me. But most importantly, I want to reach out to my sister. She’s out there somewhere. It won’t be easy, I know, but I’d like us to connect again. That’s my reason for agreeing to this interview.’