It was early in the day and the sun was shining. I needed to go into town for a few, unnecessary, things and I had the day off so I strolled there with little purpose in mind but intent on enjoying the warm spring weather. I felt very relaxed and had time to look at my surroundings as I passed through them. I saw many buildings that I hadn't realised were there and discovered shops that might be of use in the future. I breathed slowly and easily without a care in the world.

As I came around the corner into King's Street I found myself following a young girl who was being towed along by a huge Rottweiler dog. Rottweilers are always big and powerful but this one, surely, had been working out at the gym. Muscles like that do not develop naturally. It takes hours on a treadmill and weight training to hone a body like that. Pound for pound I would guess that it had the power of ten strong men, maybe more.

Coming from the opposite direction was an elderly couple towing a very small dog behind them. In dog years it was probably older than them and, obviously, wished nothing more than to be back home laying in his basket. It was wearing a thick tartan jacket and it was probably this that saved its life because, as the two dogs passed each other, the Rottweiler sprang three feet through the air and fastened its huge jaws on the mid-riff of the corgi.

The old woman screamed and promptly fainted. The old man was more concerned about his dog and shook his stick at the Rottweiler but this was about as effectual as Canute defying the sea. The Rottweiler picked the other dog up and shook it back and forth. A crowd was gathering and the big dog's owner was pleading with them to do something. Nobody moved closer than than three yards away.

I read once, when I lived in the States, of an elderly woman who had been woken in the middle of the night by a male intruder who stood by her bed with his trousers around his ankles. She was threatened with death and pretended to acquiesce with the stranger's demands. When he was feeling more relaxed she grabbed hold of him by the scrotum. He became virtually paralysed and, using various amounts of pressure, she was able to usher him out of the house, while picking up a gun on the way. When she released him he fell to the ground and was unable to stand. She raised the gun and shot him three times.

If it worked from a man then maybe it would also serve to immobilise a dog. The Rottweiler was preoccupid with the corgi, the crowd questioned why nobody did anything, the old woman, who was now sitting up, cried tears of rage while her husband continued to wave his stick. I don't know why I did it. I usually try to avoid situations that do not directly concern me and I am no great dog-lover so it surprised me, as much as anyone who was gathered there, when I rushed forward and grabbed the Rottweiler by the scrotum.

There was a sudden hush. Nobody spoke. A cave-like silence descended on the crowd. The Rottweiler stiffened and opened its jaws. The corgi fell to the ground and the old man scooped him up. I clung on tight as though my life depended on it. The dog was now laying on its side and flailing with its legs. I was afraid to let go but had no idea of how long I should continue this stance. If I released my grip would he quickly come to his senses and turn on me? I had know way of knowing. I grasped even tighter.

The Rottweiler began to howl. It was an eerie sound and one I never want to hear again. I got goose pimples, every hair on my body stood up on end and I shivered uncontrollably but I contined to hold on. I pleaded with the onlookers to phone the police and was assured that it had been done but that they were busy at the moment. They would be there as soon as they could. The Rottweiler's howl turned into a groan and its tongue hung out of its jaws. It's eyes were rolled back in their sockets and were blood-shot. I was starting to suffer cramp in my hand and wondered how long I could hold on.

A newcomer to the audience, not knowing what had happened previously, saw a middle-aged man keeping a Rottweiler imprisoned by the you-know-whats and became indignant. "That's cruel." She exclaimed. "You're hurting that poor dog. Let him go immediately." She demanded. Others, equally ignorant of the true circumstances joined in the clamour for the dog's release. "He must be drunk." Said one. "You should be ashamed of yourself." Said another.

By now my hand was, involuntarily, locked in a death grip and I could not have unfolded my fingers even if I had wished to. In as few words as possible I explained this to the indignant lady. The owner of the Rottweiler then produced a short metal bar from her handbag. "This is what my boyfriend uses to pry Butch's jaws apart when he bites something he's not supposed to." She said and handed it to a tattooed man with green teeth who claimed to know what should be done.

Everyone was taking photographs and there was almost a party atmosphere. What, for most of them, had been an ordinary, humdrum, trip to town had now become an entertaining spectacle. "Look this way, please." Said one onlooker to me as he focused his camera. "Go and stand next to the nice man with the dog." Advised a mother to her three year old daughter as she raised a mobile phone to her face.

The Rottweiler, which had lain quietly on its side staring into the distance, began to stir and come to its senses. This is what I had feard. The anaesthetic of my steel-like grip was beginning to wear off and the dog was beginning to think clearly again. He twisted his head around and stared at me. I remembered my father's advice to never look an angry dog in the eyes and turned my head to face the crowd. By now Butch was trying to get to its feet. The tatooed man with the steel bar approached. The dog pulled its lips back from its jaws, bared its teeth, and growled a warning. "I'm not going near it." Said the man as he sank back into the crowd.

Feeling was slowly returning to my hand and I felt capable of letting go. I announced my intentions to the audience and warned them to be careful. They moved several feet further away and some went to the back and watched from a greater, safer, distance.

One by one I loosened my fingers and then let go completely. The crowd gasped. I moved quickly away and was ready to run. The dog lumbered to its feet and stood there, unsteadily, for a few moments. Its owner came forward and grasped its lead. "Oh. You poor thing," she cooed, "are you alright?" He licked her hand lovingly. Individuals came from the crowd and started petting the dog. "He's so sweet." Said one, fondly. "He's adorable." Said another. A woman approached me. "You should be prosecuted." She told me. I said nothing and quietly slipped away while the crowd's attention was still focused on the dog.

I met Butch's owner a year or so later. She was alone and, when she recognised me, came over to say hello. I asked after the dog's health. "He's fine." She said. "He's as good as gold. I can take him out without a lead now. He don't bother no-one. Since that day with you he hasn't bitten a single dog. He just ignores them."

I walked off thinking that maybe I should write a dog-training manual.