Densely populated and full of contrasts, London is the capital of Britain and the capital of crime and policing. It has long been a focus for fictional crime and detection, which continues with modern-day TV series such as Luther and Marcella, and the mysteries of Robert Galbraith. Watch TV or read a crime novel, and justice will usually be delivered. A tour of the city's scenes of true crime and punishment, however, suggests that criminals often escape capture, and crimes remain unsolved.
The Bloody Tower
At busy Tower Hill Tube station, gateway to the iconic Tower of London, few people would know that crowds once gathered at nearby Trinity Square Gardens to watch public executions. The heads of the victims were displayed on spikes on London Bridge as a deterrent to others.
There are few places with such a long history of crime and punishment as the Tower. Built in the 1070s by King William I, this was a symbol of the power of the new Norman rulers. Through the centuries, it expanded into a castle complex, around which the history of England evolved. Today, the Tower is a palace, fortress, tourist attraction and national monument. For nearly 900 years, it was also a prison to some of Britain's highest-profile rebels, dissidents and criminals. Since 1100, captives as diverse as Anne Boleyn, Sir Thomas More, Guy Fawkes, William Penn (the Quaker leader) and William Davidson (the African-Caribbean rebel) have been imprisoned here. The Tower was not originally built as a prison, so captives were often held in accommodation alongside their jailers. Status and wealth mattered, as did manners. "The better you treated your jailers, the better you would be treated," says Alfred Hawkins, assistant curator of historic buildings at the Tower.
Some prisoners found ways to escape the thick stone walls. In 1101, Ranulf Flambard, bishop of Durham, got his jailers drunk before using a smuggled rope to escape. Six hundred years later, in 1715, Jacobite rebel William Maxwell escaped execution by dressing in women's clothes smuggled in by his wife.
The Bloody Tower is so called because of the disappearance in 1483 of two young princes: 12-year-old Edward V and his younger brother, Richard. What actually happened remains a mystery, although their uncle, the future Richard III, is often blamed for the crime.
The last criminals to be held at the Tower, in 1952, if only for one day (for refusing to report for national service), were the infamous East End gangsters Ronnie and Reggie Kray. It was a symbolic arrest of the identical twin brothers, who had ruled their criminal kingdom with violence and murder.
Jack the Ripper
A ten-minute walk along Royal Mint Street and across Leman Street leads to the front door of 12 Cable Street, a Victorian house converted into the Jack the Ripper Museum. The blood-red facade might suggest otherwise, but the museum dedicates much of its space to the lives of the five women who were murdered in this area in 1888. The terrible crimes shocked Victorian London and the killer came to be called "Jack the Ripper". Despite intensive police investigations and several suspects, nobody was ever convicted, and the murders remain a mystery to this day.
The six floors of the museum are darkened and atmospheric, the walls plastered with newspaper headlines from the time. Each room contains a historic tableau with models and many original artefacts. Most moving is the simple bedroom at the top of the house, which offers short biographies of each of the victims. Could more have been done to save them? Conditions on the streets of late 19th-century London were grim for the poor and the homeless, especially for women and children.
All the murdered women were victims of Victorian society, explains Sam, a researcher and historian who acts as a tour guide for the Jack the Ripper Museum and leads groups into the heart of Whitechapel. The East End has changed a lot since 1888, but it still offers a stark contrast to the wealth of the neighbouring financial district. It's no surprise that modern-day film-makers have been drawn to this atmospheric and historic quarter. Located alongside Victorian railway arches, darkened alleyways and cobbled streets are Roman and medieval ruins of the walls of the City of London, which for centuries has been policed by its own separate force.
At Mitre Square, in the shadow of a newly erected steel-and-glass office block, Sam stops to describe the discovery of the body of Catherine Eddowes in the early hours of 30 September 1888. She had spent the summer hop-picking in Kent, but in London became the victim of an infamous murderer. So gruesome was the violence against her that many believed only someone with surgical knowledge could have killed her in this way. Could the killer have been rich and powerful and therefore able to avoid police scrutiny and arrest? Sam provides the history and context of the murders - but leaves visitors to make up their own minds about the likely identity of the Ripper.
Bow Street
Catching the Tube from Liverpool Street to Holborn, it's a 15-minute walk to 28 Bow Street. Now a luxury hotel, this was once Bow Street Magistrates' Court, one of the most important courts in the city. Prisoners who stood in the dock here have included Oscar Wilde, Dr Crippen, suffragettes Sylvia and Christabel Pankhurst, and the Kray brothers.
The police station to the right of the building had offices across four floors and cells for arrests. Today, seven of those original police cells form part of the small but fascinating Bow Street Police Museum. Alongside the history of policing in London, the museum presents the true stories of the officers who served here until the station closed in 1992. They had to learn every square metre of their beat and know the people who lived and worked here. "Tea holes" were vital stops on their long walks in all sorts of weather, and the canteen was the focal point of the station. Tea, it seems, was an essential part of the fight against crime.
Bow Street has been central to the history of policing since 1740 and the small number of dedicated detectives who, in time, formed the "Bow Street Runners". In 1829, the Metropolitan Police Act created a single, unified police force to tackle crime across central London. Today's force numbers more than 43,000 police officers and staff.
Crime detection
Fifteen minutes' walk to the north-west, across St Giles, Shaftesbury Avenue and Theatreland, Denmark Street is home to the office of a less conventional detective: Cormoran Strike. It's clear from the books and TV series that London is much more than just a setting for J. K. Rowling, who writes her detective series under the name Robert Galbraith. Indeed, as Rowling has said, "London is as much a character in the Strike stories as Strike and Robin."
There are, of course, few detectives who can match the observational powers of perhaps literature's greatest detective: Sherlock Holmes. A short journey on the Underground to Baker Street leads to a search for 221B, the fictional address of Sherlock Holmes and Dr Watson. A little detective work reveals that Baker Street was much shorter in Victorian Britain. This means that 221B would actually be somewhere near where 31 Baker Street now stands. Despite this fact, coachloads of tourists from around the globe queue outside the soulless Sherlock Holmes Museum to pay homage to the creations of Arthur Conan Doyle.
Holmes and Watson first appear in the 1887 novel A Study in Scarlet, the year before the Jack the Ripper murders began. Sadly, Holmes was unable to assist in identifying the brutal killer, but his creator, Conan Doyle, believed that the Ripper may have disguised himself as a woman.
Holmes was often asked for help by detective inspector Lestrade of Scotland Yard, whose headquarters at the time were a building located between Great Scotland Yard and 4 Whitehall Place. The name Scotland Yard has since become synonymous with policing and crime detection in London.
From Charing Cross Underground station, it's a three-minute walk to the junction of Northumberland Street and Northumberland Avenue and The Sherlock Holmes public house. Inside the pub is an impressive collection of memorabilia, photos, posters and books celebrating the literary detective. Playing on the TV screens are reruns of classic Sherlock Holmes films. Upstairs, the restaurant is graced by a "study" containing a large collection of Holmes and Watson period items and mementos. In its previous existence in the 1880s as the Northumberland Hotel and Northumberland Arms, this small hotel featured in at least one Sherlock Holmes tale: The Adventure of the Noble Bachelor (1892).
Today, you can treat yourself to something off the menu (perhaps Mycroft's big or Watson's British chicken & woodland mushroom pie) and buy a Sherlock Holmes souvenir T-shirt, mug or beer mat. When you have emptied your plate, finished your drink and watched the end of a film, it's always satisfying to know that the mystery has been solved and justice served.