YORK Minster is to protect the Great East Window – one of its medieval masterpieces – with a newly developed UV shield.

The UV resistant glass will be used as part of the external protective glazing for the 15th Century window, which has been removed and is being painstakingly conserved by York Glaziers Trust.

It will become the first building in the UK to use the German made Restauro UV glass, which makes the the UV resistance an integral part of the glass itself. The work to conserve and restore the Great East Window is part of the York Minster Revealed project which is due for completion in 2016.

Mark Hosea, inset, director of York Minster Revealed, said: “We are delighted to be at the forefront of this new cutting-edge technological advance, which represents a wise investment in the long-term care of the building.”

Designed by medieval artist John Thornton, the Great East Window is the size of a tennis court and the largest single expanse of medieval glass in Britain.

The product has been developed by Glasshuette Lamberts of Germany, the world-leading producer of mouth-blown antique glass.

Previous protective glazing has acted as a weather shield and kept glass, pigments, lead and conservation materials dry, but has not been an adequate barrier to ultra violet radiation.

This affects any epoxy resin used in the conservation of the stained glass and leads to a yellowing discolouration of the resin over time.

York Minster Revealed is a five-year project due to be completed in 2016. The cost of the whole York Minster Revealed project is £20 million, of which £10.5 million has been supported with a grant from the Heritage Lottery Fund. The remainder of the money has been raised by York Minster.

Visitors to the Minster can learn more about the work to conserve the Great East Window, including seeing completed panels up close, in the Orb – a contemporary metallic dome in the cathedral’s East End.

For further details, visit yorkminster.org