The Mini Cooper S appeared in 1963 and quickly established itself as the basis for competition focused models.

Larger disc brakes, more luxurious upholstery and discreet S badges were the subtle clues, with the real changes made to the adaptable A-series engine.

With competition in mind, in 1964 Cooper produced two S models specifically for circuit racing in the under 1,000cc and under 1,300cc classes respectively, rated at 970cc and 1,275cc. The road going 970 S was a genuine homologation special, produced specifically with the under 1.0-litre class of the British Saloon Car Championship in mind.

Its specialist short stroke engine produced 65bhp but was expensive to manufacture, resulting in the 970 S becoming a special-order model.

Production lasted from June 1964 until April 1965, with just 963 examples supplied, making it one of the rarest and most sought-after production Minis. BBT 537B is a remarkably special example, having been owned by our enthusiast vendor since 1982, an ...