Monmouthshire Constabulary, which became part of Gwent Constabulary on April 1st, 1967, were early adopters of the then experimental Unit Beat Policing (UBP) methods being trialled in the early 1960s. The concept took constables off the 'beat' and into 'panda cars', allowing them to cover much larger areas and still walk a beat to meet the public. However, the advent of radios meant the UBP cars were constantly responding to calls and the beat concept gradually faded away. This car was one of six Heralds bought in September 1966 purely for UBP work, a task the reliable tight-turning Herald was ideal for. They were not fitted with blue lights or sirens in this role.
During the late 1950s, as traffic density increased and radio technology improved, the government and police started to look at different methods of policing both beat patrols and traffic management. The first 'Z' car-style policing experiments were done in Kirkby, near Liverpool, in 1959 and entailed replacing beat policemen with uniformed two-man police patrols in cars. The term 'Z car' was coined by Colonel Eric St Johnstone, then Chief constable of Lancashire, during this trial and eventually became the title of a long running BBC TV series on which St Johnstone acted as technical advisor. These experiments led to the UK officially introducing Unit Beat Policing in December 1966. Some forces resisted initially but it had become almost universal by the end of 1968.