It was almost dark by the time they stepped back out into the street, earlier than it would have been up on the islands, and everything a little unreal, leached of colour by the pools of cold light that fell from the overhead streetlamps.

“So my dad and his brother really were John and Peter,” Marsaili said, as if knowing their names in some way made them more real. “But how will we get to find out their family name?”

Fin looked thoughtful. “By talking to someone who knew them.”

“Like who?”

“Like the Kellys.”

She frowned. “How would we ever find them?”

“Well, if I were still a policeman I would have said, because they’re known to us.”

“I don’t understand.”

A young couple emerged from the blue frontage of the wine shop, bottles clunking in a paper bag. She slipped her arm through his, and their voices came like chattering birds in the twilight.

Fin said, “The Kellys are a well-known crime family in Edinburgh, Marsaili. Have been for years. Started out in what was then the slum village of Dean. Drugs, prostitution. They’ve even been implicated in a number of gangland killings, though nothing was ever proved.”

“You know them?” Marsaili couldn’t keep the incredulity out of her voice.

“I never had any dealings with them, no. But I do know that my old DCI did. He was my boss when I was first in the force. Jack Walker. Retired now.” He took out his mobile. “He’d probably be happy to meet us for a drink.”

Someone seemed to be going around Edinburgh painting shopfronts, bars and restaurants in primary colours. Vandals with a misplaced sense of civic pride. The Windsor Buffet at the top of Leith Walk was a virulent green, the former Scottish Television studios next door to it a shocking blue. Yellows and reds featured up and down the street, along with more greens and blues. All topped by drab sandstone tenements, some of which had been stone-cleaned, while others remained blackened by the years, like bad teeth in a brave smile.

The Windsor was nearly full, but Jack Walker had reserved them an alcove at the back. He looked curiously at Marsaili when they were introduced, but didn’t ask. He ordered beers for Fin and himself, and a glass of white wine for Marsaili. He was a big man with wide shoulders, and an untidy shock of white Brillo-Pad hair. For all that he must have been in his mid-seventies, he was not a man you would choose to pick a fight with. He had a sunbed-tanned face and emerald eyes that never quite achieved the same apparent warmth as the sardonic smile that played constantly about his lips.

He shook his head gravely. “You don’t want to mess with the Kellys, Fin. They’re bad bastards.”