While I still had the phone in my hand I called the hospital and they told me that Aidan was asleep and his parents were still with him.

A headache began to rage between my temples and my thoughts continued to burn like a fuse.

I checked my watch, saw it was eight o’clock already and time to make up my mind either way.

My heart was beating its way out of my chest so I sat down and switched on the TV. I wanted to know if there had been any further developments since I’d left the office.

I happened to catch the start of a recorded interview with Roy Slack, who looked as though he’d been trampled under a herd of buffalo.

As I listened I scowled my hatred at the screen and felt my pulse escalate. The bastard was clearly in his element, acting like he was an innocent victim while slagging off the police.

But his face betrayed him. There was the smug expression that he was trying hard to conceal. And there was the glint of amusement in his eyes.

He thought he was untouchable. That the law was powerless to stop his grotesque killing spree, especially after what had happened to him. But this sick, arrogant performance was surely enough to drive any copper to breaking point.

Including me.

I grunted out a bitter laugh and said aloud, ‘You’ve made up my mind for me, you evil fucker. I’ll do whatever it takes now to put you and that psycho bitch away.’

I spent the next fifteen minutes working out what I was going to do, while praying that Danny Carver would be in and alone when I got to his house.

Then having come up with the bare bones of a plan, I hurried upstairs to change into a dark polo sweater, jeans and a hooded windcheater jacket.

Back downstairs I grabbed my scarf and gloves from the table in the hall and made sure my shoulder bag contained the Taser gun, a set of handcuffs and the car keys.

I then stormed out of the front door, ready and willing to break the law in the name of justice.

Aidan and I shared an ageing Peugeot 307. It didn’t get much use because driving in London was usually a nightmare and it was much easier to take the bus or tube.

But I didn’t anticipate the roads would be very busy this evening and it was only two miles from Balham to Streatham. I put Danny Carver’s address into the satnav and got going.