Foster was born to Robert Foster and Lilian Smith in 1935 in Reddish, Stockport, Cheshire. They moved, soon after his birth, two miles to 4 Crescent Grove in Levenshulme, Manchester, which they rented for fourteen shillings (70p) a week: Foster has no recollection of Reddish. Foster's parents were diligent, hard workers – so diligent that Foster, as an only child, felt their heavy workload restricted his relationship with them and he was often looked after by neighbours or other family members. He attended Burnage Grammar School for Boys in Burnage. In a "Guardian" interview in 1999, Foster said he always felt 'different' at school and was bullied and he retired into the world of books. He considered himself quiet and awkward in his early years often making faux pas.