It’s difficult to imagine today’s police force chasing down criminals in a tiny, two-seater convertible but in the 1960s, it was a reality.

Back then, a small number of Triumph TR4 police cars were commissioned into service and 4100 HJ (pictured above) found a home with Southend-on-Sea County Borough Constabulary in May of 1962.

The original car, which could reach a top speed in excess of 100 mph, was supplied with a specification including: Pye radio, Winkworth bell, air horns, a windscreen mounted hand-operated lamp, front and rear police signs and a rear stop sign.

The car was eventually retired from service and sold to a private vendor in 1991 where it was restored to original police specification.

So detailed was the recent restoration, that where special equipment was missing, items were sourced with the assistance of members of Police Car UK.

The tiny Triumph will go on sale next month at Historics’ Brooklands-based auction.

Retired Superintendent Bill Burles of Southend-on-Sea Constabulary recalled how 4100 HJ was allocated the task of ‘fast pursuit car’ that went out on two shifts a day, seven days a week, clocking up approximately 1000 miles a week.

Officers invariably drove the car with the top down and always wore their helmets with chinstraps in place.

The small slice of British history comes with a large file that contains some paraphernalia of the time, including a copy of ‘Advanced Driving Explained’ by Inspector W.H Jobson, priced one shilling and sixpence, with a picture of 4100 HJ on the cover.

With its unique history and exemplary condition, Historics expects strong interest from enthusiasts and collectors, with the car anticipated to achieve a price in the region of £35,000 – £40,000.

The Triumph TR4 police car will be presented for sale by Historics at Brooklands on Saturday June 1, 2013.