A silver fork and spoon designed by Charles Rennie Mackintosh is to be auctioned to help restore tea rooms which he also created.

The cutlery, valued at £15,000-£20,000, will go under the hammer at Lyon & Turnbull in Edinburgh later this month, with the proceeds going to The Willow Tea Rooms Trust in Glasgow.

The fork and spoon were part of a 12-place setting of dining cutlery commissioned by artists Jessie and Fra Newbery in 1902 as a gift from her parents.

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Each set contained a soup spoon, dessert spoon, dinner fork and dessert fork, with knives supplied separately from a stock pattern.

The silver fork and spoon were donated by Celia Sinclair, founder and chair of The Willow Tea Rooms Trust, which has been created to restore the building at 217 Sauchiehall Street in Glasgow.

She said: "I am delighted that I am able to offer these beautiful objects for sale to benefit the work we are doing at the trust. The money raised from the sale will go towards the restoration of the tea rooms."

Renowned as the most elegant of Miss Cranston's four tea rooms, the Willow Tea Rooms opened in October 1903, with Mackintosh at work designing it from the beginning of that year, if not earlier.

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The trust purchased the premises in July 2014 and as well as restoring the tea rooms, it plans to incorporate a visitor centre to celebrate the building and other works by Mackintosh.

It will also highlight the achievements of Miss Cranston, an early female entrepreneur.

John Mackie, decorative arts specialist at Lyon & Turnbull, said: "I greatly admire the work the trust has undertaken to ensure the legacy of Mackintosh will be here for future generations to enjoy."

Jessie Newbery was a Scottish artist and embroiderer, and was one of the artists known as the Glasgow Girls.

She created the department of embroidery at the Glasgow School of Art, and married Fra Newbery, director of the School, in 1889.

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Under Mr Newbery's leadership, the School developed an international reputation and he helped commission Mackintosh as architect for the now-famous School of Art building.

The commission for their cutlery was handled by a jeweller's in Glasgow, Edwards & Company, and the cutlery was made by DW Hislop, a Glasgow silversmith who worked with Mackintosh on other projects.

All of the cutlery was later divided equally between the Newberys' daughters Mary and Elsie, with Mary's pieces sold separately during the 1970s and 1980s.

The fork and spoon will go under the hammer on October 26.