One of them wore a baseball cap and seemed to be the leader. He swatted the mystery man across the side of the head and the trilby hat went flying, revealing a shaven skull.

“Christ, what have we got here?” the youth in the baseball cap demanded. “A bloody Chink. Hold him while I give him a slapping.”

Chavasse, seeing the man’s face clear in the light of the street lamp, knew what he was. Tibetan. The other two lads grabbed the man by the arms and the one in the baseball cap raised a fist.

Chavasse didn’t say a word, simply stamped hard against the back of the lad’s left knee, sending him sprawling. The youth lay there for a moment, glowering up.

“Let’s call it a night,” Chavasse said, putting down his umbrella.

The other two released the Tibetan and rushed in. Chavasse rammed the end of the umbrella hard into the groin of one and turned sideways, then stamped on the kneecap of the second, sending him down with a cry of agony.

He heard a click behind and the Tibetan called, “Watch out!”

As Chavasse turned, the one in the baseball cap was on his feet, a switchblade in one hand, murder in his eyes. Suddenly, Earl Jackson seemed to materialise from the gloom like some dark shadow.

“Can anyone join in?” he enquired.

The youth turned and slashed at him. Jackson caught the wrist with effortless ease, then twisted hard. The youth dropped the knife and cried out in pain as something snapped.

Jackson picked up the knife, stepped on the blade and dropped it down the gutter drain. The other two were on their feet, but in poor condition. Baseball cap was sobbing in pain.

“Nigger bastard,” he snarled.

“That’s right, boy, and don’t you forget it. I’m your worst nightmare. Now go.”