Ann Schlee, who has died aged 89, was one of those rare novelists who found success writing for both children and adults. The Vandal, a dystopian tale of alienation in Thatcherite Britain, won the 1980 Guardian Children’s Fiction Prize, while Rhine Journey, the story of a Victorian spinster’s emotional awakening on a European excursion, was shortlisted for the 1981 Booker Prize and was nearly adapted by Tom Stoppard into a script.