Never-before-seen objects from Scotland Yard's crime museum are to go on public display for the first time later this year.
The "Black Museum", currently housed in room 101 of the Met's Victoria Street headquarters, has been open only to police and invited guests since it was established in 1875.
In October around 500 items from its hoard of 20,000 objects and evidence from some of the UK's most notorious crimes will go on display at the Museum of London.
The exhibition will use real-life case files to tell the stories of the gruesome Dr Crippen murder of 1910, East End gangland bosses the Kray twins, the Great Train Robbery of 1963, and Millennium Dome diamond heist of 2000.
It will include the death mask of executed criminal Robert Marley from 1856, execution ropes and three gallstones which failed to dissolve in the acid bath murders of the 1940s.
There will also be possessions of Ronnie Biggs and other members of the Great Train Robbery gang recovered from their hideout a nd a briefcase with a syringe and poison which the Krays planned to use for witness intimidation.
The museum's visitors' book reveals that it has received an eclectic mix of high-profile guests over the years, including King George V, Sherlock Holmes author Sir Arthur Conan Doyle, illusionist Harry Houdini and comedy double act Stan Laurel and Oliver Hardy.
Sharon Ament, director of the Museum of London, said: "Crime is an unfortunate by-product of big-city life, and a reality that Londoners are all too familiar with.
"Challenging and disturbing; familiar and unsettling, The Crime Museum Uncovered will use select objects from this extraordinary, hidden collection to consider the changing nature of crime and advances in detection over the last 140 years.
"Through focusing on people - victims, perpetrators and police officers - we'll use real objects to explore the human stories behind some of the UK's most well-known crimes, personalising what is so often de-personalised.
"And in doing so, we'll confront how, as a society, we respond when normality is shattered, lives are torn apart and we need to rebuild."
Met Commissioner Sir Bernard Hogan-Howe said: "The artefacts held in the museum will provide visitors with an insight into the evolution of crime investigation and criminal justice.
"The public will view exhibits from some of the most complex, and indeed notorious, criminal investigations carried out by the Met, and discover how such crimes were solved."
The Crime Museum Uncovered will run from October 9 to April 10 next year.