was held at the Museum of London from 9 October 2015 to 10 April 2016. Following the exhibition the Museum reopened in 2018 in a "dark and dramatic" room in the basement of the Building designed by Allford Hall Monaghan Morris in collaboration with engineering consultancy Arup. Though the 2015–2016 exhibition was the only time a large number of exhibits have been displayed to the public, individual objects have been loaned to exhibitions at other museums in 2019–2020. This included objects from Leatherslade Farm in a Great Train Robbery exhibition at the Postal Museum and a cigarette lighter with a hidden compartment from the Krogers in a GCHQ exhibition at the Science Museum, whilst exhibits from the trial of Roger Casement have been on loan to Kerry County Museum since 2016. Collections The museum displays more than 500 exhibits, each at a constant temperature of . These include historic collections and more recent artefacts, including a substantial collection of melee weapons (some overt, some concealed, all of which have been used in murders or serious assaults in London), shotguns disguised as umbrellas and numerous walking-stick swords. The museum also contains a selection of hangman's nooses, including that used to perform the UK's last-ever execution, and death masks made for criminals executed at Newgate Prison and acquired in 1902 on the prison's closure. There are also displays from famous cases which include Charlie Peace and letters allegedly written by Jack the Ripper. The infamous From Hell letter is not part of the collection. The more recent exhibits on display include the ricin-filled pellet that killed Bulgarian dissident Georgi Markov in 1978, a model of the possible umbrella that fired the pellet, the fake De Beers diamond from the Millennium Dome heist and Dennis Nilsen's actual stove and bathtub. Other items no longer on public display include items that once belonged to Charles Black, the most prolific counterfeiter in the Western Hemisphere. These include a set of printing plates, a remarkable series of forged banknotes, and a cunningly hollowed-out kitchen door once used to conceal them. Cases on display The eponymous pieces of evidence from the February 1918 "Badge and Button Murder", also known as the Eltham Common murder Udham Singh, an Indian revolutionary who shot and killed Michael O'Dwyer, the former Lieutenant Governor of the Punjab in British India. Ruth Ellis, the last woman to be executed in the United Kingdom,