Aidan’s anger had gradually subsided during the course of the evening, and when he returned from taking Mum home, he opened a fresh bottle of wine, filled two glasses, and got me to sit next to him on the sofa.

‘Your mum’s not here now so it’s time to be brutally honest with me, Laura,’ he’d said. ‘I want to know how concerned we should be about this threat, given that your team are going after some of the city’s most powerful criminals.’

So I’d told him what I honestly believed – that this was now a threat that had to be taken very seriously, and I was pretty sure my superiors would agree with me.

We’d talked about it until after midnight, and I’d been wide awake when we’d finally climbed into bed.

Aidan had dropped off fairly quickly, but for me it wasn’t so easy. I was too rattled and the adrenalin continued to pump through my veins at a rate of knots.

So now I was tired as well as anxious, and that was no way to start a new day.

Our mornings were always a rush so we didn’t have time for another conversation about the death threat. But Aidan made me promise to call or text him if there were any significant developments during the day.

Before we parted we hugged each other and it was longer and tighter than usual.

‘Stay safe, sweetheart,’ he said, and his words sent a shudder along my spine.

That was probably the moment when I fully realised just how unsettled I’d become.

Before leaving Aidan, I asked him to keep an eye on my mother in school. I then called her on the way to the station and actually felt relieved when she answered.

She said she was already in her office but admitted to getting very little sleep during the night.

‘I’ll keep you updated on what’s going on,’ I said. ‘But please try not to worry. You’ll be fine.’

‘It’s not me I’m worried about, Laura. It’s you. I keep thinking about your father and how easy it was for his killer to get to him. I wouldn’t want to live if the same thing happened to you.’

‘It won’t and you have to believe that.’

‘How can I if you stay on this task force?’

‘Stepping back from it is not an option, Mum. You know that.’

‘Well then, don’t tell me not to worry.’

On the tube I couldn’t stop thinking about what she’d said and I could feel the anxiety building up inside me. By the time I got to the Yard my head was spinning and a cold sweat had settled on my skin.

Once in the office it soon became apparent that close family members of the other detectives were also freaking out.