The poster, which dates from 1895, was designed for an exhibition at the Glasgow Institute of Fine Arts. A year later, Mackintosh (1868-1928) won the architectural competition to design and furnish the Glasgow School of Art.
Richard Barclay of Christie's, who has seen only three copies of the design in 30 years, said: 'It is astonishing that so little material from such an influential artist comes on to the open market.' Mr Barclay was 'secretly expecting' the poster to make more than estimate as there was strong interest from major institutions and dealers.
The previous auction record for a British poster - pounds 7,700 - has been held since 1988 by Alexander Alexeieff's The Night Scotsman, and Christie's.
Mr Barclay said the poster market continued to be relatively unaffected by the recession - 'it stagnated, but it has never dropped' - and he noted an increase in the number of English buyers in what is an international market.
The Mackintosh example was one of nearly 200 posters of the nineteenth and twentieth centuries at the sale. Posters by Toulouse-Lautrec were among the few casualties because the Japanese, who used to collect him, have largely stopped buying.
Various posters commissioned from the French artist Jean Dupas (1882-1964) by London Transport in the 1930s to publicise the Tube sold for up to pounds 4,600.
Mr Barclay said it may be 40 or 50 years before today's LT posters are worth anything.Reuse content