The fourth book in the Inspector Rebus series, 1992

The first thing to acknowledge is that the constituency of North and South Esk is the author's creation. However, you don't need to be Mungo Park to work out that there must be some correlation between North and South Esk and the real world, Edinburgh being a real place, and 'south and east of Edinburgh' being a vaguely definable geographical area.

In fact, North and South Esk bears some resemblance to the Midlothian parliamentary constituency – prior to 1983's Boundary Commission changes – but also bites a small southernmost chunk out of the present Edinburgh Pentlands constituency and a westerly chunk out of East Lothian constituency.

Gregor Jack, too, is fiction, and bears no resemblance to any MP.

Thanks are due to the following for their inestimable help: Alex Eadie, who was until his retirement the MP for Midlothian; John Home Robertson MP; Professor Busuttil, Regius Professor of Forensic Medicine, University of Edinburgh; Lothian and Borders Police; City of Edinburgh Police; the staff of the Edinburgh Room, Edinburgh Central Library; the staff of the National Library of Scotland; staff and customers of Sandy Bell's, the Oxford Bar, Mather's (West End), dark's Bar and the Green Tree.

The wonder of it was that the neighbours hadn't complained, hadn't even – as many of them later told the newsmen -realized. Not until that night, the night their sleep was disturbed by sudden activity in the street. Cars, vans, policemen, the static chatter of radios. Not that the noise ever got out of hand. The whole operation was directed with such speed and, yes, even good humour that there were those who slept through the excitement.

I want courtesy,' Chief Superintendent 'Farmer' Watson had explained to his men in the briefing room that evening. 'It may be a hoor-hoose, but it's on the right side of town, if you take my meaning. No telling who might be in there. We might even come across our own dear Chief Constable.'

Watson grinned, to let them know he was joking. But some of the officers in the room, knowing the CC better than Watson himself apparently did, exchanged glances and wry smiles.

'Right,' said Watson, 'let's go through the plan of attack one more time

Christ, he's loving this, thought Detective Inspector John Rebus. He's loving every minute. And why not? This was Watson's baby after all, and it was to be a home birth. Which was to say, Watson was going to be in charge all the way from immaculate conception to immaculate delivery.

Maybe it was a male menopause thing, this need to flex a bit of muscle. Most of the chief supers Rebus had known in his twenty years on the force had been content to push pens over paper and wait for retirement day. But not Watson. Watson was like Channel Four: full of independent programmes of minority interest. He didn't make waves exactly, but by Christ he splashed like hell.

And now he even seemed to have an informer, an invisible somebody who had whispered in his ear the word 'brothel'. Sin and debauchery! Watson's hard Presbyterian heart had been stirred to righteous indignation. He was the kind of Highland Christian who found sex within marriage just about acceptable – his son and daughter were proof – but who baulked at anything and everything else. If there was an active brothel in Edinburgh, Watson wanted it shut down with prejudice.

But then the informer had provided an address, and this caused a certain hesitation. The brothel was in one of the better streets of the New Town, quiet Georgian terraces, lined with trees and Saabs and Volvos, the houses filled with professional people: lawyers, surgeons, university professors. This was no seaman's bawdy-house, no series of damp, dark rooms above a dockside pub. This was, as Rebus himself had offered, an Establishment establishment. Watson hadn't seen the joke.

Watch had been kept for several days and nights, courtesy of unmarked cars and unremarkable plainclothes men. Until there could be little doubt: whatever was happening inside the shuttered rooms, it was happening after midnight and it was happening briskly. Interestingly, few of the many men arrived by car. But a watchful detective constable, taking a leak in the dead of night, discovered why. The men were parking their cars in side streets and walking the hundred yards or so to the front door of the four-storey house. Perhaps this was house policy: the slamming of after-hours car doors would arouse suspicion in the street. Or perhaps it was in the visitors' own interests not to leave their cars in broad streetlight, where they might be recognized…

Registration numbers were taken and checked, as were photographs of visitors to the house. The owner of the house itself was traced. He owned half a French vineyard as well as several properties in Edinburgh, and lived in Bordeaux the year through. His solicitor had been responsible for letting the house to a Mrs Croft, a very genteel lady in her fifties. According to the solicitor, she paid her rent promptly and in cash. Was there any problem…?

No problem, he was assured, but if he could keep the conversation to himself.

Meantime, the car owners had turned out to be businessmen, some local, but the majority visiting the city from south of the border. Heartened by this, Watson had started planning the raid. With his usual blend of wit and acumen, he chose to call it Operation Creeper.

'Brothel creepers, you see, John.'

'Yes sir,' Rebus answered. 'I used to own a pair myself. I've often wondered how they got the name.'

Watson shrugged. He was not a man to be sidetracked. 'Never mind the creepers,' he said. 'Let's just get the creeps.'

The house, it was reckoned, would be doing good business by midnight. One o'clock Saturday morning was chosen as the time of the raid. The warrants were ready. Every man in the team knew his place. And the solicitor had even come up with plans of the house, which had been memorized by the officers.

'It's a bloody warren,' Watson had said.

'No problem, sir, so long as we've got enough ferrets.'

In truth, Rebus wasn't looking forward to this evening's work. Brothels might be illegal, but they fulfilled a need and if they veered towards respectability, as this one certainly did, then what was the problem? He could see some of this doubt reflected in Watson's eyes. But Watson had been enthusiastic from the first, and to pull back now was unthinkable, would seem a sign of weakness. So, with nobody really keen for it, Operation Creeper went ahead. While other, meaner streets went unpatrolled. While domestic violence took its toll. While the Water of Leith drowning still remained to be solved…

'Okay, in we go.'

They left their cars and vans and marched towards the front door. Knocked quietly. The door was opened from within, and then things began to move like a video on double-speed. Other doors were opened… how many doors ' could a house have? Knock first, then open. Yes, they were being courteous.