‘I’ll need some office space,’ Zen remarked. ‘What have you got available?’

The clerk consulted a wall-chart.

‘How long are you going to be here?’

Zen shrugged.

‘Hard to say. A week or two at least.’

‘There’s a desk free in three one nine until the seventeenth. Gatti’s on holiday until then.’

Room 319 was a small office at the front of the building, overlooking the canal. Zen was looking down at a refrigerated barge marked GELATI SANSON squeezing past the police launches moored outside the Questura when the door opened to admit Aldo Valentini, whose name figured alongside that of the absent Gatti on the door.

Valentini was a mild, scholarly-looking man with Armani glasses and a skimpy blond beard like grass which has been growing under a plank. He seemed pleased to have company, and suggested that he and Zen pop out to get some breakfast. As they emerged into the sunlight, bucking the incoming tide of staff hastening to sign themselves in so that they could slip out again, Valentini inquired about the reason for Zen’s transfer.

‘You must be joking!’ he barked in the slightly nasal accent of his native Ferrara. ‘Ada Zulian! A woman who doesn’t even know the right time…’

Zen gestured impatiently.

‘What does that matter, as long as she knows the right people?’

Aldo Valentini conceded the point with a shrug. He led the way to a bar at the end of the quay. A red neon sign over the door read Bar dei Greci, after the nearby Orthodox church. There was no sign of any Greeks inside, although the barman’s accent suggested that he was from somewhere well to the south of Chioggia.

‘All the same, la Zulian!’ exclaimed Valentini when they had ordered coffee. ‘God almighty, she’s been in and out of the loony bin like a yo-yo for the last twenty years. This complaint of hers ended up on my desk, largely because no one else would touch it with a bargepole.’