The City will become the capital of crime in October when never-before-seen items from the Met Police's notorious "black museum" go on show.

Grisly items include: the death mask of executed criminal Robert Marley, a briefcase concealing a poisoned syringe that the Krays were going to use on a witness, the paraphernalia of Acid Bath murderer John Haigh and the kit of the Great Train Robbers.

Previously these items were only on view to police professionals and guests but The Crime Museum Uncovered, at Museum Of London, will make them accessible to all while telling the story of the collection from its formation in 1875.

The Acid Bath Murderer: Objects relating to the murder of Mrs Olive Durand-Deacon by John Haigh, 1949

The Crime Museum’s Visitors’ Book reveals an eclectic list of high-profile guests over the years. King George V, Sherlock Holmes author Sir Arthur Conan Doyle, illusionist, Harry Houdini and comedy double act, Stan Laurel and Oliver Hardy have all stepped inside the infamous “black museum”, housed within the Metropolitan Police’s HQ, New Scotland Yard.

The exhibition, which is being created with the support of the Metropolitan Police Service and the Mayor’s Office for Policing And Crime will take visitors on a journey through real cases and how they were investigated.

It will bring them close to the objects and evidence from some of the UK’s most notorious crimes, including the Acid Bath Murderer of 1949, the Great Train Robbery of 1963 and the Millennium Dome Diamond Heist of 2000. It will also examine some of the challenges faced in policing the capital.

Terrorism: Shrapnel from an unexploded Fenian bomb found at Paddington Station 1884

Museum Of London director Sharon Ament aid: “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 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.”

Capital Punishment: Death mask of Robert Marley, 1856

Met Police Commissioner Sir Bernard Hogan-Howe said: “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.”

Mayor of London Boris Johnson said: “Many of the policing methods now used by forces all over the world were developed here in the capital by our pioneering policing techniques.

“This exhibition will bring this story alive, in some instances out from behind closed doors for the first time, allowing us to reflect on the victims at the centre of each of these cases and learn more about how the creativity of the past has shaped the way the police work today.”

The Crime Museum Uncovered will run from October 9 to April 10, 2016. Tickets available from £12.50 online; £15 on the door.

Inside the Metropolitan Police's hidden Crime Museum at New Scotland Yard, 2015