The Black Museum, or The Crime Museum of Scotland Yard, is a collection of criminal memorabilia kept at New Scotland Yard, headquarters of the Metropolitan Police Service in London, England. The museum came into existence sometime in 1874, although unofficially. It was housed at Scotland Yard, and grew from the collection of prisoners' property gathered under the authority of the Prisoners Property Act of 1869. The act was intended to help the police in their study of crime and criminals. By 1875, it had become an official museum, although not open to the public, with a police inspector and a police constable assigned to official duty there.