On first sight, this old CD would appear to be a simple library of “technology” sounds to be played as accompaniment to appalling low-budget films about “the future”, as perceived by annoying drama students marching around abandoned warehouses dressed in tin foil.

However, in truth it is the result of years of high-level research and the completion of what could crudely be labelled a time machine. American scientists on the military base at Roswell managed in 1956 to delve into the time space continuum to make this recording. They appeared again in 1998, ran into the Chappell studios and put their recordings into the hands of a bemused sound engineer before collapsing into piles of dust. These were then put onto CD and sold on the open market, nobody realising their true value until now.

Value unknown: item seized by government officials.