The cache of boardroom accessories, including tables, sets of monks’ chairs, elaborate partners’ desks, coat stands and even typists’ desks were turned out by hand from Thompson’s studio in Kilburn.
They were commissioned in the 1930s by the owners of the Horlicks nighttime beverage, for their vast new factory in Slough.
Workmen clearing it for demolition found the furniture stunningly intact on a floor of the building that had been seldom used for years.
The collection of 45 items yielded nearly £300,000 when it went under the hammer at Sworders in Essex.
A spokesman for the firm said: “A strong provenance such as this is always expected to command interest. But expectations were completely exceeded.”
The highest priced item was a personalised oak dresser, bearing the date 1930, which was valued at up to £8,000 but sold for £43,050 – the second highest price ever for a Mouseman piece.
An oak partners’ desk sold for £15,990 and a pair of monks’ armchairs fetched £5,658.
Thompson devised his enduring trademark both as a symbol of “industry in quiet places” and from a conversation with a fellow carver about being as poor as church mice.
His work for Horlicks is believed to have begun with a commission from Sir Peter Horlick, one of the family firm’s directors, for furniture for a private house or estate.
The last major collection of his work to be sold was a clearance of library furniture from Leeds Girls’ High School, 10 years ago.
The record price for a Mouseman piece, at $70,000, is held by Sotheby’s in New York, for a 1923 two-section cupboard with ironwork by the Kirkbymoorside blacksmith, Will Dawson.