The author Jane Gardam has died at the age of 96, her publisher has announced. The double Costa Award winner is best known for her novel Old Filth, and had a writing career spanning 50 years.

Gardam was born in Yorkshire in 1928 and grew up in Redcar. She was the daughter of the maths master at the local grammar school and a mother who longed to be a writer, and she spent her holidays on her grandfather’s farm in Cumberland. 

Gardam attended Bedford College (part of the University of London) after the Second World War and married a barrister, elements of whom found their way into her Old Filth (an acronym of Failed in London Try Hong Kong). When she finally left the youngest of her three children at primary school she said that "she ran home as fast as she could to begin writing". She once said she "would have died if she couldn’t get her first book published – she was possessed".

Gardam is the only person to have won the Costa (then Whitbread) Award in two categories for The Hollow Land (Abacus) in the children’s category and The Queen of the Tambourine (Sinclair-Stevenson) in the novel category. She won the Heywood Hill Award for a lifetime’s contribution to the enjoyment of literature in 1999, and was shortlisted for the Booker, Orange and Folio prizes. She had legions of admirers, including Ian McEwan, who called her "a treasure of English contemporary writing"; Chimamanda Ngozi Adichie who "adored her"; Hilary Mantel, who called her "humane and wonderfully funny"; as well as Ann Patchett, Meg Wolitzer, Kit de Waal, Nina Stibbe and  Amanda Craig.

Her publisher said she was "hugely loved by us all", adding: "Her warmth, humour and wisdom are quite irreplaceable."