A window, thought to date from medieval times, has been discovered during building works at the Bedford Hotel in Tavistock.

The hotel is built on the site of the former Benedictine Tavistock Abbey which was founded before 981 and which by the end of the medieval period had became the wealthiest and most important monastery in Devon.

During construction work to build a new function room in a rear courtyard of the hotel, builders removing slate cladding from a wall revealed a small blocked trefoil-headed Hurdwick stone framed window.

An archaeological investigation by Dr Stuart Blaylock of Exeter Archaeology puts the window as late medieval with rubble masonry adjacent from the 14th or 15th century.

Dr Blaylock said the window has not been seen in living memory, probably having been blocked up some time in the nineteenth century and that the find helps deepen understanding of the history of the abbey.

He said: 'If you think of Tavistock Abbey as a jigsaw from which we only have ten to 15% of the pieces remaining and no picture on the box, we have just found another piece. Any find of this sort is significant as it is a finite resource.

'It has filled out the picture and added to what we know about this little corner of the Abbey.'

Dr Blaylock explained that the find actually complicates understanding of this area of the abbey remains, as it shows more of a sequence of structural history than had previously been evident.

He believes, however, that this part of the abbey was probably used as part of the abbot's lodgings.

The window, which stands at roughly hip height in the south wall of the new function room, and whose frames are constructed of locally-quarried Hurdwick stone, will be conserved and protected by a toughened glass panel.

Philip Davies, chairman and managing director of Warm Welcome Hotels, said: 'We are delighted that this important historical feature has been revealed during work on the new function room and that we are able to conserve it for future generations.'

Architect for the project, Stephen Whettem, said: 'A key aim of the design of the new room was to bring into the public realm some of the hidden parts of Tavistock's heritage.

'The function room was designed as a simple roof canopy with fully glazed external walls, giving views of a number of important and historic buildings that surround it. The discovery of this very attractive and historic window opening is a real bonus.'

The Bedford Hotel has an interesting archaeological history, having been built on the site of the abbey refectory in the early eighteenth century as a private house, before being Tudorised in the early nineteenth century by Sir Jeffrey Wyatville.

He was the architect famous for the Duke of Bedford's Endsleigh House at Milton Abbot, and for work on Chatsworth House, Woburn Abbey and restoration of medieval parts of Windsor Castle.

In 1830 a plaster vaulted ballroom was added by Plymouth's most celebrated Victorian architect John Foulston.

The new function room was added by the current owners Warm Welcome Hotels and will offer a venue in central Tavistock for conferences, weddings and other occasions.

Five nineteenth century window panes have also been replaced with specially commissioned textured glass by Launceston based artist Alan Endacott of Angel Stained Glass.