His brain misted over for a moment, then cleared suddenly. It had an old trick of doing that. The new gain in clarity was always startling, and never more so than now. When he had been taken with Dogson to the Supervisor’s office three weeks before, he had noted, mechanically, that the sanctum was housed in a block of offices which clustered and leaned on one another in a large ramshackle building, looking from the outside like a ware­house. That building had several entrances. Some of them gave on to the street outside. One of them gave on the wharf where he was now standing.

It was a choice between a fantastic risk on the one hand, and the complete certainty of capture on the other. Keeping out of sight as far as possible, he moved along to within twenty yards of the door he was making for. Dusk was beginning to fall, but he knew that this was no great help to him: within a few minutes, when the police had gathered fresh men and spread the net systematically over the area, a suspect would be picked up even if it were pitch dark. As yet, however, the general alarm had not been given, and the small, blurred drama was acting itself out in a framework of general indifference and orderliness. Workmen were leaning against a shed wall, watching with happy curiosity the knot of officers moving along the wharf; elsewhere the routine was going on in ignorance of any disturbance of its peace.

Amazingly, no one stopped Charles, no one pointed him out and began to run towards him, no one heeded him. There was the lull of a few seconds before the oiled machinery of pursuit came into action, and, by pure coincidence, he had achieved the miracle of timing that enabled him to use those few seconds. He entered the building by a clouded glass door that looked as if it were only occasionally used and then not by anyone of importance. A flight of stairs led upward. Long, dark corridors branched. The office staff had long gone home, but it was not yet time for the caretaker to inspect and lock up. Again he had chanced on the one brief space of time that most favoured him.

He lost his way; and, pausing to look out of a window, found that he was already on the side of the building that overlooked the street. The nearest door on the street side, if they had not already placed a guard over it, would free him, temporarily, at least.

Footsteps clumped up the stairs, and a bowed figure with an oval pail in one hand and a broom in the other came scowling up to him. But the voice that accompanied it was casual, not angry.

‘Been workin’ late, aincher?’

‘I had to see about the catgut. Writing a report on the catgut,’ Charles’s whirling memory prompted him to stammer.