From under his coat he produced a long coil of silk rope that he had wound round and round his thin body. At one end of the rope was a rubber-covered hook, and at the other end a heavily padded ring.

He stepped out on to the window sill and looked up. Above him was the balcony of one of the bedrooms on the tenth floor. He tossed up the hook which caught in a stone projection and held.

He climbed up the rope as effortlessly and as quickly as a monkey runs up a tree. He reached the balcony, swung himself over the balustrade and dropped on to hands and knees.

He peered through the window into an empty room, then he looked over the balustrade and stood watching the activity below until he had satisfied himself no one from the ground had seen him.

He climbed up on to the balustrade and looked up at the perpendicular roof some twenty feet or so above him. A stout rain gutter ran the length of the roof, and he tossed up his hook again. The hook caught in the gutter, and he pulled, testing the gutter’s strength. It neither bent nor creaked under his persistent pulling, and without more ado he launched himself into space and went swarming up the rope until his claw-like hands got a grip on the gutter.

He pulled himself up as far as his waist above the gutter, shifted his handholds, got one leg up and along the gutter, his foot in the gutter. There he remained while he adjusted his balance.

The steep roof towered above him. Far below, the bright floodlights, the blue water of the swimming-pool and the continual arrival of cars, looked like a child’s toy laid out on a green carpet.

Ferrari began to lean forward very slowly, and at the same time he drew up his other leg and got that along the gutter. He was now balanced only on his hands, and the slightest error of judgment would pitch him backwards into the black gulf below.

He was quite calm, but he knew his danger.

When he had told Maurer he believed he was the only man in the world who could do this job he had been sincere. This moment of balancing was the hardest task he had ever attempted. He wasn’t frightened, but he did wonder if he hadn’t overestimated his skill.