Then I knelt down, pushed him over onto his front, and cuffed his hands behind his back.

‘This is a two-shot Taser,’ I told him and held it in front of his face that was pressed against the carpet. ‘If you don’t do as I say I’ll give you another blast.’

I put my knee against the small of his back and let him feel the weight of me. His body went still and he began to mumble incoherently.

I got up off him and hauled him to his feet where he wobbled unsteadily. Then I gripped the cuffs with one hand and shoved the Taser into his back with the other.

‘Is there anyone else here?’ I said.

‘What the hell is going on?’ he spluttered back at me. ‘Who are you?’

‘Just answer the question, Carver. Are you alone?’

He threw himself against the wall and tried to turn to face me. But I responded by yanking his arms up behind his back, which made him scream.

‘OK, OK,’ he yelped. ‘There’s no one else here, for Christ’s sake.’

I pushed him along the hall to the first open door, which led into a large, modern kitchen. Once inside, I fired the second shot from the Taser. This time the point of impact was midway between his shoulder blades, and he went crashing to the floor.

While he reacted again like he was having a fit, I took his belt from his jeans and used it to secure his ankles together.

By the time I’d done that the vessels were throbbing at my temples and the breath was roaring in my ears. But I’d managed to bring down the notorious Rottweiler in less than two minutes. And I felt good about that.

So now the bastard was completely at my mercy, and the first stage of my plan was complete.

Oh, how the mighty fall!

That was my initial reaction as I looked down on the trussed-up figure of one of the most feared men in the London underworld.

‘You don’t look so tough now,’ I said. ‘I can’t imagine why they call you The Rottweiler. A poodle would be more fitting.’

He rolled onto his side and stared up at me, confusion writ large on his face.

‘Do I know you?’ he snarled.

‘I’ll ask the questions,’ I said, speaking through my linen scarf while trying to make my voice sound gruff. ‘It’s why I’m here. And why I’m going to hurt you if you don’t answer them.’

He narrowed his shark-like eyes. ‘Have you just escaped from a fucking mad house? If not then that’s where you belong.’

I lifted my right shoe and brought it down hard on his chest. He screwed up his face and let out a sharp grunt of pain. He was lucky that I was wearing flats and not heels.