I told her that I was confident it wouldn’t be long now before we caught the assassin and the creature who was paying her to wreak havoc. But it was a lie. I knew we weren’t making any progress and we wouldn’t unless we found that chink in Roy Slack’s armour.

And it was going to be just as difficult to find the assassin. There were thousands of motorcycle riders in London, most of them wearing leathers and helmets. If we started flagging them down randomly we’d just cause major chaos.

I told my mother I’d call her back later in the day and just as I put the phone away Sergeant Wilks popped his head in. He said he was going off duty and a new security detail had taken up position in the corridor.

It should have reassured me, made me feel safer, but instead it sparked a fresh surge of anger. My chest started to feel tight, and a red mist clouded my vision.

‘What are you thinking, Laura?’ Aidan asked me.

I took a slow breath and said, ‘I’m thinking how much easier it would be to stop this if we didn’t have to abide by the law.’

Aidan frowned. ‘And if you were given free reign what would you do?’

I didn’t have to think about it. ‘I’d put thumb screws on Roy Slack and the heavies who protect him and I’d squeeze until they coughed up.’

If only to avenge the death of our unborn baby.

‘So why don’t your lot do just that if you’re so convinced he’s behind it – instead of spouting a load of bullshit about lack of evidence?’

‘Because we’re coppers, Aidan. Not criminals. And that’s a hard truth that villains like Roy Slack have been exploiting for decades.’

‘But it’s ridiculous. What if he’s too clever for you and you don’t find any proof? What then? Do you just accept that there’s nothing you can do about it? Christ, Laura, three police officers have already been murdered along with a woman whose only crime was being married to one. Another officer was shot and wounded just like me. And yet the bloke you believe hired the killer is free to orchestrate more carnage. It makes no bloody sense.’

To the general public, especially those who’d been victims of crime, it didn’t make much sense. It was the reason that as police officers we were often asked why men we knew to be major criminals were allowed to go on flaunting the law for years. They didn’t appreciate that reasonable suspicion and probable cause were not enough. In the UK you were presumed innocent until proven guilty.