In more than ten years as a forensic pathologist in the capital, Dr Shepherd has dealt with death in all its guises - suicides, strangulations, hangings, stabbings, multiple shootings, multiple accidents, child abuse, child murder and even assassinations.
Employed by Guy's Hospital Medical School, Dr Shepherd is an approved Home Office pathologist, which means he is qualified to perform murder post mortems for the police. The majority of cases that Guy's handles are routine - sudden and unnatural deaths - but they also have responsibility for suspicious deaths in 98 per cent of London as well as the Home Counties, excluding Kent and Essex.
This arrangement covers a population of 20 million, some of whom have a healthy appetite for crime and violence.
The basis of forensic pathology is the examination and interpretation of injuries. Dr Shepherd performs between 700 and 800 post mortems each year, of which roughly 100 belong in the 'suspicious category. Fifty of them turn out to be murder - an average of one a week. Many of these inevitably make headlines.
'We're on call 24 hours a day. When I set off from home in the morning, I never quite know where I'll find myself by evening,' says Dr Shepherd. He could find himself called out to attend to a contract killing in some remote beauty spot, or, more likely, a kicking or stamping death outside a busy pub.
From the age of nine, Dick Shepherd knew what he wanted to be. A friend brought one of Professor Keith Simpson's grisly textbooks into school. 'What fascinated me was the investigation side of the job, and the fact that you could look at something like that and form conclusions. Those conclusions could help convict someone. . .or free them.
Now married with a teenage son and daughter, Dr Shepherd's passion for medical detective work remains undiminished.
His office in Guy's is airy and cheerful within limits, given the collection of ancient specimens in glass and bookshelves which contain everything you ever wanted to know about asphyxiation, decomposition rates and the life-cycle of the blowfly maggot.
The mass of books is also a clue that forensic pathology is, above all, an intellectual pursuit. The essentials of forensic pathology are still the simple tools: scalpel, knife, pair of scissors - and a keen mind.
On to the vexed question of dissection. How can Dr Shepherd bring himself to do it day after day? 'Pathologists are no more morbid than the members of any other profession. On the whole, they tend to be lively and extroverted characters. We don't perform post mortems for fun. We do it for very good reasons.
'The first rule of the post-mortem room is that we treat the body with respect. I can cope because death is a routine experience for me. . .I see death in a very sanitised way.
'The first post mortem I did was a very peculiar experience, making incisions, removing organs. . .actually not just the first one, but the first hundred.
High levels of concentration are demanded from the pathologist these days: a
murder post mortem usually lasts three to ten hours - a 'routine post mortem runs at around 20 minutes.
Dr Shepherd and his colleagues take precautions. 'Aids, now present throughout the population, has raised the level of concern in our job about the handling of fluids. We protect ourselves by assuming that every body is a serious risk of infection. We see plenty of bodies with track marks, injection sites, the stigmata of the drug addict. . .they're the easy ones to spot.'
The unwritten motto of the profession is 'Look under one more layer; you never know what you'll find. In some cases of manual strangulation there are no marks visible on the neck, but the post mortem allows you to have a good look at the neck muscles for signs of bruising. Some bruises, he says, can go all the way down to the bone through two or three inches of muscle - a good indication of the amount of force used - and what was thought to be natural death turns out to be murder.
He sees amazing things. From extraordinary conditions such as situs inversus - where everything in the body is the wrong way round, yet works perfectly - to the worst forms of human depravity.
'I don't think I'm shock-able. I'm sometimes slightly surprised about what I see. I'm quite capable of believing that one human being can do almost anything to another.
'Sometimes I do get upset on the way back from a case, I pull over to a layby, stop the car for a few minutes and just think quietly to myself. Then I drive on.
Is London getting more violent? Dr Shepherd points out that he has a distorted view. He admits he has seen a slight increase in gunshot wounds. It is also true to say that more people are being stabbed in incidents that would once have been simple muggings.
However, there's no point in worrying. 'You're more likely,' he concludes, 'to win the pools and then be struck by lightning than be murdered at random on London's streets.'
The city is a great place to work. 'Here you'll see the biggest selection of cases in any one year. There's no such thing as 'the standard strangling' or 'the standard stabbing'. The variations in each case add spice. Everybody is fascinated by murder. . .it just happens that murder is my line.