It was the hottest day of the month so far, although there were still five more days of July remaining. But the forecast suggested that August would be no cooler.

I was sitting in my office above Belgravia police station in central London, with a cup of fresh coffee in front of me and beside it a completed report for the Crown Prosecution Service. My in-tray was empty and the commander had taken the day off. My jacket was hanging over the back of my chair, and I was contemplating the possibility of actually having a weekend off to do exactly as I pleased. And that was to do nothing. What could be better than that?

Unfortunately what we anticipate rarely occurs, and it is particularly foolish for a detective chief inspector who is attached to the Homicide and Major Crime Command of the Metropolitan Police to think such things. Especially at half past two on a Friday afternoon.

'Excuse me, sir.' Detective Sergeant Colin Wilberforce, the incident-room manager, appeared in my office doorway. Colin is a mild sort of guy who's happily married to Sonia, has three children and lives in Orpington. But this gentle giant becomes a ferocious rugby player when he turns out for the Metropolitan Police and has a cauliflower ear to prove his on-field aggressive qualities.

'What is it, Colin?' I was disconcerted by the expression on Wilberforce's craggy face. It had a certain triumphant look about it, and I imagined it was the sort of triumphant look that appears on his face when he's barged his way through the opposing players and is in sight of a touchdown.

'We've got one, sir, and Mr Dean has given it to you.'

'By which I take it that, in his infinite wisdom, Mr Dean has decided to ruin my weekend.' But I couldn't really complain, Patrick Dean was the detective superintendent in charge of our bit of HMCC and his allocation of cases was always scrupulously fair.

'Yes, sir,' said Wilberforce, his face not betraying the slightest amusement, even though I knew that inside he was laughing like a drain. It was all right for him: he had the weekend off.

'What's the SP?' I asked wearily, as I stood up and put on my jacket. Short for starting price, SP is a bit of terminology the police have lifted from the sport of kings, but to CID officers it's a desire to know what's happened so far.

Wilberforce glanced at some sort of electronic gismo he was holding in his hand. 'The body of a deceased male was found in Apartment E, Cockcroft Lodge, Cockcroft Grove, North Sheen, sir. First officers on the scene were told that it was the deceased's home address.' After grinning owlishly, he added, 'It would appear that he'd been shot, sir.'

'Has he been identified?'

'Sort of. His name's Richard Cooper according to the man who called the police.'

'And who was that?

'A man by the name of Dennis Jones who claims to be a friend of Cooper. He's been detained at the apartment pending interview.'

'When did this drama unfold, Colin?'

Wilberforce glanced at his gadget again. 'It was approximately thirteen thirty hours when Jones found the body, sir.' And anticipating my next question, he added, 'Dave Poole is in the car park ready and waiting, and Miss Ebdon is assembling the rest of the team.'

Detective Sergeant Dave Poole is my black bag carrier. And to clear up any ambiguity, it is Dave who is black not the bag. In point of fact there isn't a bag any more, but the term has stuck. Of Caribbean descent, his grandfather arrived in the 1950s and set up practice as a medical doctor in Bethnal Green; his father is a chartered accountant, but Dave, after obtaining a good English degree at London University, claims that in a moment of insanity he joined the Metropolitan Police until he could find a proper job. And I can honestly say that he's the best assistant I've ever had working with me. What I forget, he remembers.

Adopting a mock West Indian sing-song accent in place of his native cockney, Dave frequently refers to himself as the black sheep of the family, thus alarming the more sensitive of those among our hierarchy who consider racial diversity to be far more important than fighting crime. But there's not a lot they can do about Dave making racist remarks about himself, especially when doing so he adopts a sort of downtrodden expression.

I made my way to the car park, where Dave was waiting with the engine running.

The distance to North Sheen from Belgravia is about ten miles, but given that London is probably the most congested city in Europe, Dave did well to get us there in slightly less than forty-five minutes, by dint of what he calls positive motoring.

One glance at the exterior of Cockcroft Lodge was enough to confirm that it comprised a series of upmarket apartment blocks. Looking at the pristine lawns and delicately playing fountains in the gardens, I guessed that my salary wouldn't even cover the maintenance. And that was before I discovered that underground there existed a swimming pool, a gymnasium and a squash court and that there were tennis courts in the gardens at the rear. All of which pointed to the residents being seriously rich people.

A youthful inspector, clutching a clipboard and looking terribly important, stood in the main entrance to the nearest of the three apartment blocks. He raised his pen and opened his mouth as I approached, but I answered the question I knew he was going to ask before he'd uttered a word.

'DCI Harry Brock, HMCC.'

'Thank you, sir,' said the inspector, and waggled his pen at Dave with an officious sort of flourish.

'Colour Sergeant Poole, ditto, sah!' Dave, having guessed that the inspector was one of the aforementioned diversity worriers, adopted his West Indian sing-song accent and contrived to look like a recently emancipated slave.

The inspector gulped and scribbled on his clipboard. So far he had remained silent, but as he probably hadn't anything useful to contribute that was undoubtedly for the best.

A uniformed constable whose ravaged and weary seen-it-all face gave him the appearance of one old enough to be the inspector's father smirked and lifted the blue-and-white tape. 'First floor, guv. The hat inspector's there.'

The HAT inspector is so called not because of a propensity for eccentric headgear or, for that matter, any sort of headgear. The acronym HAT means Homicide Assessment Team, a roving band of detective inspectors, male and female, who are called upon to determine if a suspicious death is a homicide. And if it is, that's where I come in. There was a time when the Murder Squad at Scotland Yard was so small that its members knew each other, but now there are over seven hundred of us. Nevertheless, we're told by the inhabitants of that self-deluding dream factory known as the Home Office that incidents of major crime are on the decline.

Dave and I took the stairs to the first floor. I have a negative attitude towards lifts; they tend to malfunction when you're in a hurry, and it's embarrassing if you get stuck in a lift when you're on your way to investigate a murder. It happened to me some years ago, but I can still recall the collective sniggering of the firefighters who eventually liberated me.

'Afternoon, guv.'

'Still not doing me any favours, then, Jack.' I had first met Jack Noble, the HAT inspector, at the scene of a murder one snowy February morning in Chelsea.

'Sorry about that, guv'nor. People will go about...