Baird sat astride a thick branch, his back braced against the trunk, some thirty feet above ground.

Across his knees lay a .22 Winchester repeater, fitted with a telescopic sight and silencer. He was wearing a loose jacket and trousers of green and yellow camouflage: the kind of kit the U.S. Army issued for jungle fighting. He had smeared burnt cork over his face. No one looking up at the tree, even with the aid of field-glasses, could spot him.

Below him, also astride a branch and similarly dressed, Rico sat and sweated. Slung over his shoulder was a canvas sack which contained a dozen smoke bombs Baird had given him.

They could see the convicts working in the blazing sunshine, manhandling the mud as it poured from the steam shovel into the trucks; sweat poured off them as they toiled. They worked stripped to the waist; old, battered straw hats shielded their shaven heads from the sun.

Baird surveyed the scene through a powerful pair of glasses. Up to now he had counted three guards, and was trying to locate the other two. Two of the guards were on the bridge house of the dipper dredge.

One of them had an automatic rifle under his arm; the other appeared to have only a pistol at his hip. The third guard walked slowly up and down on the narrow deck of the hydraulic dredge. He was armed with an automatic rifle and a .45 Smith and Wesson.

Baird shifted his glasses to a building made of logs and thatched with saw-grass that stood in a clearing away from the bank. He spotted another guard sitting in the shade, astride a Browning machine-gun, covering the road that led out of the swamp.

The machine-gun startled Baird. Noddy hadn’t said anything about a machine-gun.

‘Take a look at that guy in front of the hut,’ he said in a low voice to Rico. ‘He’s the one I’ve got to take care of.’

Rico raised his glasses and nearly dropped them when he saw the Browning.