Square Four

997cc ohv four || 480lb || 45mpg || 100mph || (Mk.1 and Mk.2) || 1949-1959

The famous British postwar four is one of those special machines that attracts a premium. Despite having a one-litre engine it is not a high-performance mount, but it is incredibly smooth – if a little noisy. Early models are prone to overheating if travelling in traffic and the solo handling can be a little challenging at speed, not least because the Anstey link plunger rear end can struggle with the weight and performance and can be hard to set up. The brakes can also have difficulty coping with arresting your speed, more obviously so if two-up or hauling a sidecar. A highly desirable and functional bike with a unique cachet and solidly rising in value. Mk2 bikes are easier to rebuild. For real exclusivity, track down one of the 22 1960s Healey specials.

Prices: low £10,000 || high £16,000