Comment made on http://www.fire-engine-photos.com/picture/number40166 with some background on the Coventry colour experiment.
The experiment with Coventry commenced during 1966 and
concluded on the 1st April 1974. The West Midlands fire service then
commenced using a videnfeld livery (dayglow) orange Coventry was merged
into the West Midlands you may be surprised to learn the Coventry
appliance were downgraded on specification as they were considered to
far advanced for the day and this would mean upgrading the new West
Midlands deliveries to compete with the Coventry appliances. Not all of
Coventrys original appliances made it to yellow, even in 1974 some were
still red livery. Also l will mention that the brigade did
experimentation with the use of orange flashing lights as these proved
higher visibility than their blue counterparts this however was aborted
on legal grounds the following brigades followed Coventry with the
yellow liveries. West Sussex Fire Brigade, Wallasey, York, Rotherham,
Exeter (isolated vehicles), West Riding (only trailed), Tynemouth
(isolated vehicle), Sheffield (isolated vehicle) Northampton also
adopted yellow but this was a golden yellow (used by GPO of the day) The
Brigades of St Helens West Riding and in later years the Isle of Wight
adopted brilliant white with the borough of Rochdale having white fronts
on their appliances,
Added by Bob Carver on 29 September 2016.