A Channel 5 documentary on British lighthouses will be airing soon, with an episode in the series devoted to a rock lighthouse, approximately 20 miles off the Pembrokeshire coast.

The second series of Lighthouses: Building The Impossible will begin airing this Friday, April 29, and will be hosted by presenter, engineer and adventurer Rob Bell.

The second episode of the series looks at the Smalls Lighthouse, located in the Irish Sea and only a few miles from the Pembrokeshire coast.

The series is being produced by production company Viacom International Media Networks.

A spokesperson from Viacom said: “Rob Bell explores the bizarre history of The Smalls lighthouse - one of Britain’s most remote offshore lighthouses.

“Twenty miles off the Pembrokeshire coast, its isolated location on a reef in the Irish Sea has challenged builders, architects, and keepers for over 200 years, leaving it wreathed in dark tales and mystery.

Milford Mercury: Rob Bell, presenter of Lighthouses: Building the ImpossibleRob Bell, presenter of Lighthouses: Building the Impossible

“Rob reveals The Smalls’ macabre story of the keeper who was forced to share a prison-like cabin with his dead companion - a tale of anguish and madness that even inspired Hollywood movies.

“The stories of the first efforts to claim the reef by a violin maker also beggar belief, symbolised by the ramshackle wooden contraption that finally emerged from the barren rock.

"Taking on the sea himself, Rob demonstrates why the genius thinking behind this unlikely-looking lighthouse proved revolutionary, prevailing against Mother Nature for 80 years. 

“But tragedy was never far away at The Smalls, and a rogue wave was to find the weak point in its design, resulting in the loss of yet another keeper.

“To find out whether tall tales of surprise rogue waves could actually be true, Rob is wowed by Edinburgh University’s cutting-edge wave tank facility, as it precisely replicates nature to sort fact from fiction once and for all.

"The last keepers at The Smalls also recount their own memories of one of the most spectacularly isolated workplaces in Britain.

“In the historic docks of Liverpool, Rob uncovers an astounding reward for building and maintaining The Smalls Lighthouse so far from land.”