Peregrine was born in Crovan's Gate in 1974 to Percy (1943-) and Margaret Percival (1941-). He was the fourth out of five children. As a child, he was fascinated by the little engines of the Skarloey Railway. He became an engine driver for The Arlesdale Railway in 1996 and kept the position for four years. He then decided to return to the Skarloey Railway and was the assistant manager to Roger Sam (1948-). When Sam retired in 2005, Percival was offered to take his place and did so gladly.
Percival married Polly Maithwaite (1975-) in 2000 and they had five children: Percy, Pauline (both born 2001), Lucy (born 2002), Gilbert (born 2003) and Anne (born 2002), who they adopted from Africa.