Are these chilling century-old photographs proof actual ghosts have been caught on camera?

A series of chilling century-old photographs which appear to show haunting images of people beyond the grave have been discovered.

The collection of four "spirit photograph" slides are understood to have been taken by ghost photographers in the 1920s or 1930s.

Spirit or ghost photography, beginning in the 19th century, aimed to capture images of ghosts and other spiritual entities, often around people called sitters who posed in the hope apparitions of their departed loved ones would be caught on camera.

Snappers William Mumler, from the US, and William Hope, of Crewe, England, were pioneers and ran bustling businesses taking photos of people with their supposed dead relatives.

Hope was a member of the well-known spiritualists' group, the Crewe Circle.

Both were actually later exposed as frauds, using double exposure techniques.

However, there are true believers, such as Sherlock Holmes author Sir Arthur Conan Doyle, who refused to accept evidence of their trickery, and believe they show real spooks caught on camera.

Now, four such slides by an unknown photographer, but in the style of Hope are being sold at auction by Sworders on July 30.

They are being sold with an estimate of £400 to £600.

A Sworders spokesperson said: "These 1920s or 30s [images] are a rare group of four spirit/ghost photographic magic lantern slides, various sitters and spirit images, with bizarrely one of the spirits looking to be possibly an Arctic explorer.