Once upon a time, an attractive investment opportunity arrived

Grown-ups are rediscovering a love for children's book illustrations

From the Gruffalo to the Grinch and Winnie the Pooh to the Wild Things: these are the creatures that stalk childhood imaginations. But now grown-ups are taking a keen interest in these literary beasts – and it isn't just nostalgia.

Galleries report that original book illustrations are being seen as a good investment as well as something familiar to hang on the walls.

Buyers have realised that illustrations by well-known artists are relatively affordable with prices in the low hundreds of pounds. Now demand is pushing up costs, with some illustrators' work trebling in value over the past five years.

The Illustration Cupboard, a London gallery specialising in such works, says turnover has leapt 90 per cent in three years. Its founder John Huddy described it as an "encouraging, exciting time". The gallery recently sold an E H Shepard illustration for a 1931 version of Kenneth Grahame's The Wind in the Willows for £50,000. Other works by best-selling illustrators – including the Alfie author, Shirley Hughes, and David McKee, who created Mr Benn and Elmer the patchwork elephant – have trebled in value.

Chris Beetles, owner of London's Beetles gallery, has noticed a "marked change" in the past two months. He said "normal people" – as opposed to "high rollers" – fed up with getting low returns on their money, are buying illustrations they like confident these will keep their value.

Luke Heron, director of the art fund StoryBoard Assets, which invests in book illustrations, said that people tend to invest in physical assets at times of economic uncertainty. At some point, he predicts, illustrations will sell for "silly prices".

Auction houses are taking note. On Tuesday, Christie's will sell both newer and rare collections, including an illustration for the 1983 edition of Wind in the Willows by Harry Hargreaves, while Sotheby's has more than 20 lots of illustrations later this month, including work by Shepard, Arthur Rackham and Edmund Dulac.

Quentin Blake, renowned for his close collaboration with Roald Dahl, admitted there was more interest in illustration, adding that it was an "everyday language" people had rather taken for granted. He claimed there had been a degree of "intellectual snobbery" in the past, with people sometimes ashamed that illustration was done to commission for money.