Born in Bradford,Yorkshire, Swindells worked for a newspaper after leaving school aged 15. He served with the Royal Air Force and held various jobs before training as a primary school teacher. His first novel, When Darkness Comes (1973), was written while he was still in training. Swindells combined writing with teaching until 1980 when he took up writing full-time. He is still writing as he approaches his 71st birthday (March 20, 2010).

He first won the Children's Book Award with Brother in the Land (1984), a novel set in a post-apocalyptic world. Swindells was a supporter of the Campaign for Nuclear Disarmament and is quoted as saying that the work "... came out of my own anger and frustration ... you can’t kill selectively with nuclear weapons, you wipe out millions of people ...". Swindells also won the award for Room 13 (1990), Nightmare Stairs (Short novel, 1998) and Blitzed (Younger readers, 2003). His young adult novel Stone Cold (1993), which dealt with homelessness, won the Carnegie Medal in 1993.