In providing for their chief of detectives to have his home within the Castle walls, the authorities got excellent value for their money. Whether at his office or in his house, John Mallon received a constant inflow of information on crime and security matters from all over the country, but particularly from across Dublin city. He insisted upon it. Woe betide the duty detective manning the public office at Exchange Court who delayed the transmission of any important intelligence to him in his parlour, or even in his bedroom.

A sheet of icy rain swept across the Lower Yard as Mallon opened the door in response to Swallow’s tug on the bell-chain. The chief of detectives put a warning finger to his lips, gesturing him to be silent.

‘Detective Inspector, come in. I have two gentlemen inside who were just leaving.’

He led him into the parlour at the front of the house. It was pleasantly warm, in contrast with the outdoor chill, and it smelled of whiskey and tobacco smoke. A good turf fire burned cheerily in the grate. Swallow saw two empty glass tumblers on a low table.

Two men were standing by the fireplace, evidently preparing to leave. Swallow knew immediately that they were from the office of the assistant under-secretary for security, Howard Smith Berry, in the Castle’s Upper Yard. Smith Berry’s background was in military intelligence in India, and since his appointment to Dublin he had built a separate and supposedly secret security unit, perhaps a score of men, to act under his personal direction. The detectives of G-Division detested them. Most of the secret service men were ex-military, unfamiliar with police work. The G-men regarded them as blunderers and spies. And every G-man believed that they too were being spied upon by Smith Berry’s men.

Swallow knew the younger of the men now standing in John Mallon’s parlour. Perhaps thirty-five years of age, he was clean-shaven, of average height and athletic build. He was Major Nigel Kelly. At least that was the name by which he had introduced himself. He was an unknown quantity. Swallow had found it impossible to identify his previous posting from the army list when he consulted it. Their paths had crossed unpleasantly, and they had clashed more than once in the past. Kelly had openly voiced his contempt for the way G-Division did its work. Swallow thought him a fraud and a poseur. Military men were usually open about their regimental background, but Kelly never spoke of his. Swallow was good on accents. He could always tell a speaker’s county, and often what part of that county, but Kelly’s eluded him. It was English, but overlaid with something Irish, probably Antrim or Down, he reckoned. And a touch of colonial as well.