It all started when my dog, Oscar was hit by a passing van. I took him to the vet, who checked him over (he is fine), but while I was waiting I found myself on the receiving end of a love bomb from a rather gorgeous cat in a cage next to me. This cat did not lack confidence.

He waved his paw at me as though to beckon me over and then went through a series of impressive tricks like rolling over, standing on two feet, all the while fixing me with an almost hypnotic stare. It was as though he was sending me some telepathic message. Take... me... home... now." Whatever it was, it worked.

The cat, Roo, had been shot by some bastard with an air rifle and had been taken into care by the vets. I agreed to adopt him, and upon my return from holiday in France, Roo (now renamed Captain Kangaroo) arrived at our place to start his new life.

The vet did give me a veiled warning. She told me that Captain had made quite a social leap as he had lived in what laughably passes for "the hood" in Cheltenham. "He has... attitude when facing up to other animals in the surgery," she said cryptically. I reassured her that all our animals were very friendly and that they would not hold Captain's inner-city background against him.

The vets left and I showed Captain round the place. He seemed very satisfied with his new living arrangements and, unlike other cats we've had, showed few signs of nerves or unease. In fact, he made himself very much at home and was soon sprawled on my chest on the sofa as we watched television together. He was purring away and even seemed to share my enthusiasm for the show, Storage Wars. We were a match made in heaven, I now had what I always wanted – a furry television companion.

All was well for half an hour until the dogs returned from their walk. Fitzgerald, our new Labrador puppy, bounded into the room to come and tell me about his adventures. Captain suddenly changed – the purring ceased and his body went taut. He jumped up and attacked poor Fitzgerald, a kindly puppy without a mean bone in his body.

Captain swiped him, hissed like an angry cobra and chased the poor mutt out of the room. This was a professional job. This was not the work of a cat who had felt threatened, this was clearly something instinctive, something primal. Captain hopped back on to my chest purring away as though to say,"Don't worry, that idiot won't be back."

I tried to explain that Fitzgerald had just the same rights as the Captain to wander around but he just fixed me with quite a creepy stare that made me go silent. I slipped out to find Fitzgerald having a minor nervous breakdown. Clearly terrified of the Captain, he refused to re-enter the room.

It's been three days now, and I am firmly convinced that Captain was some kind of enforcer in his old life. Things had clearly got hot for him in the hood, leading to the shooting. I have somehow, inadvertently adopted a gangster cat and he now rules my home with an iron paw. Help!