He was born in Tadworth, Surrey, to Dorothy Martin (a watercolourist) and Thomas Prest (a civil servant).
[1] He performed his national service in the Royal Air Force before attending King's College, Cambridge in 1949.
[1][2] Whilst at Balliol, Prest campaigned for the admittance of women into the College and also for more state-educated pupils to be educated there.
[2] After marrying Susan Davis in 1961, Prest moved to Walled Cottage in Wheatley, Oxfordshire.
[1] After his death, The Guardian said Prest would be "admired by future historians for his scholarship, humanity and intellectual independence".