[5][6][7] Oldfield was born and raised in the farming community of Monk Fryston, a small village in the West Riding of Yorkshire a few miles from Castleford.
[10] Oldfield joined the West Riding Police in 1947, specialising in the Criminal Investigation Department (CID), where he rose through the ranks.
[12] The success of obtaining a conviction and heavy sentence for Ward provided a significant boost to Oldfield's reputation,[13] and on 27 May 1976 he was promoted to be Assistant Chief Constable for Crime at West Yorkshire Police.
[14] However the M62 investigation would prove to be rushed, careless and ultimately forged, but culminated in Ward claiming culpability for the M62 coach bombing and two separate, non-fatal explosions.
The following day, in the presence of Oldfield, Ward wrote a confession claiming culpability for transporting the explosives used in the September 1973 Euston bombing.
[20] Several years after Oldfield's death, Ward's conviction was overturned as the forensic tests were discredited and her confession found to be the product of mental illness.
In overturning the conviction, the Court of Appeal strongly criticised Oldfield for not disclosing a series of interviews with Ward to her defence team.
[7] As Assistant Chief Constable, Oldfield took the lead in the police inquiry when, starting in 1975, several women were found murdered or horrifically injured in Leeds and Bradford.
Oldfield was convinced that the real murderer had been in contact and spent a great deal of time in the Northeast around Sunderland, as the accent of the man on the tape was determined to come from the Castletown area in the town.
During this time, Chief Constable Ronald Gregory praised his officers who had worked hard and whose health had suffered under the pressure, including media criticism.