AN ancient gravestone that dates back to the days when the Vikings raided the Clyde is to leave Scotland for the first time in its 1100-year history.

The intricately carved 'Hogsback Stone', which is part of a collection at Govan Old Church in Glasgow, is being loaned to the British Museum for an upcoming exhibition on the Norsemen in Britain.

Weighing in at half a tonne, the slab is one of five to be found in Govan and once marked the resting place of a nobleman in the Ninth Century AD.

During that time Govan was the seat of the kings of Strathclyde and the political, administrative and spiritual capital lands of the ancient Britons and one of the most important settlements in the UK.

When the stone was carved the Vikings were roaming the seas and conquering much of northern Europe, and had begun to exert their influence in the west coast of Scotland.

The artwork on the Hogback Stones is thought to represent stylised Viking houses for the dead, and its discovery at Govan shows that there was an increasing exchange of ideas and cultural practices between the Norse invaders and the ancient people of Scotland.

There has been a place of worship at the site of Old Govan Church for more than 1500 years and the stones and relics were found in a nearby graveyard.

Stephen Driscoll, Professor of Historical Archaeology at the University of Glasgow, said: "The Govan Stones are central to our understanding of the important but poorly documented kingdom of Strathclyde.

"Their presence gives us clues towards the complex and evolving society that existed within the region at this time. While the wording on the stones is mostly Celtic, the shape and some of the designs are taken from the Viking tradition, giving us the idea that the old kingdom was a melting pot of indigenous Celtic and Briton cultural influences and newer Norse ones."

The gravestone will form part of an exhibition called 'Vikings: Life and Legend' which will run at the British Museum until June 2014. It will be returned once the exhibition finishes.

The stone will be part of the inaugural exhibition for the Sainsbury Exhibition Gallery, a custom-built space currently being built as part of the British Museum's new World Centre for Exhibitions and Conservation.

The four other 'Hogsback Stones' will remain on display at Govan Old Church, along with 26 other ancient monuments found in the area, including the only stone sarcophagus dating back to before the Norman Conquest of Britain in 1066, which is the only one of its kind to be found in Scotland.