1967: A Motoring Year in 5 Images Plans for the London Ringway 2 were published. Only a short stretch of the ringway, at first called M11 extension and intended to be called the M15, was actually built and now forms part of the North Circular. Breathalysers were introduced by the Labour Minister of Transport Barbara Castle. The limit was set at 80mg per 100ml of breath. Refusal to provide a specimen for laboratory test became an offence as de facto failing the test. Rover launched the final version of the P5 with a 3.5 litre V8 engine. Piper Cars started to sell their specialised Piper GT as a kit for home completion. It used Triumph Herald’s front suspension and a Ford rear axle and was able to take a variety of engines. The national 70 mph limit was introduced in Great Britain. Introduced as an experiment in 1965, it was made permanent. It is not referred to as the ’70 mph’ limit, but as ‘the national speed limit’, permitting future changes without the need for major new legislation.