The company's native United Kingdom market did not use the 2.6 L version, which was used in vehicles of Australian and South African manufacture.

The 1500 was a four-door saloon, the Nomad a five-door hatchback which whilst bearing a similarity in looks to the Maxi, was an entirely local design.

This, together with the gearbox in sump design, forced a high bonnet line when the E series was fitted to smaller cars, something which infamously compromised the styling of the Austin Allegro, which was originally intended to sport a much sleeker appearance until it was decided by BL management that it would use the E series in its largest engine variants.

A higher compression version of the 1.7 was developed utilising a twin carburettor set up with increased valve lift and flat-topped pistons.

The lack of water jacketing caused considerable development problems when the 1.5 L in the Austin Maxi needed an optional larger engine size.

The 1.5 L four-cylinder E series could not be readily bored out, the placing of the gearbox directly underneath the sump made stroking the engine more difficult, and the Maxi was too narrow to accommodate a large-capacity six-cylinder.

The R series was effectively a stop-gap solution for the Austin Maestro, and is all but identical to the E-Series, the main difference being modifications to take an end-on transmission, in place of the BMC 'transmission-in-sump' arrangement.

The S-Series was a more thorough redesign, featuring a belt-drive camshaft in place of the E-series chain and a completely new cylinder head.

However cost constraints and the recent merger with Leyland/Triumph meant that all development was shelved on the project, as it would already be in a crowded sector within the company.

Alec Issigonis utilised the 1.5 E Series in the gearless Mini which he privately worked on during his time as a consultant in his later years after his official retirement from BLMC.

AC Cars of Surrey needing a new fashionable mid engine car purchased the design and name with the idea of launching it at the 1973 Motor Show, however British Leyland stated that they could not guarantee supply of E series power and transmission units from Crofton Hackett due to the impending launch of the Allegro.

It then suffered in development, owing to Type 1 crash approval, and was finally launched at the 1978 Motor Show as the AC 3000ME[1]