Alien overlords, a giant robot and cavemen... welcome to the feverish imagination of Roy Spence.

A true sci-fi extravaganza, Specimens is one of the most ambitious films that the brothers made. Switching from the Stone Age to the present day, it features intricate sets and models and an explosive set-piece filmed in Ballymagowan Quarry. As with a number of their other creations, Specimens bagged the brothers a 10 of The Best, World Amatuer Film of the Year prize at the British Film Institute, a feat they achieved at least 10 times between 1965 and 1985.

Twin brothers Roy and Noel Spence have been making films like this for over fifty years; with subjects including crafty leprechauns, creatures from outer space, fifties rock 'n' rollers and the undead. You can enjoy many of these fantastical creations on BFI player. This film is courtesy of Roy Spence and is held in the Irish Film Archive.