Stylistically, it went against the sharp-edged styling cues largely led by Italian designer Giorgetto Giugiaro that were becoming fashionable, and featured rounded panel work.

The original styling proposal, by Harris Mann, had the same sleek, wedge-like shape of the Princess, but because British Leyland management, keen to control costs, wanted to install the existing E-Series engine and bulky heating system from the Marina, it became impossible to incorporate the low bonnet line as envisaged: the bodyshell began to look more and more bloated and tubby.

This was acceptable to BL, however, which according to Jeff Daniels' book British Leyland, The Truth About The Cars, published in 1980, wanted to follow the Citroën approach of combining advanced technology with styling that eschewed mainstream trends in order to create long-lasting "timeless" models.

This featured a prominent grille at the front and an interior enhanced by a range of modifications designed to attract traditionally inclined customers, including: special seats upholstered in real leather, with reclining backrests; deep-pile carpets; extra sound insulation; a new instrument panel in walnut; walnut folding tables for the rear passengers; nylon headlining; and for the luggage, a fully trimmed boot.

One batch of 48 'Mark Three' CKD kits was shipped from England after NZMC had decided to drop the Allegro in 1980, and these were assembled and sold, also in brown or cream; these rare cars have four round headlights rather than two square units, and different tail lights, plus a restyled dashboard.

Launched in time for the London Motor Show in October 1975, the Allegro 2 had the same bodyshells but featured a new grille, reversing lights on most models and some interior changes to increase rear seat room.

General Motors had also introduced the Vauxhall Chevette, a slightly smaller car, but which competed with larger rivals due to the practicality of its hatchback body.

At the end of 1976 British Leyland confirmed that it was holding exploratory talks with trades union representatives concerning the possible transfer of Allegro production from Longbridge to the company's plant at Seneffe in Belgium.

[6] The Equipe was intended to compete with the Golf GT and the Escort RS; by now though the aging Allegro with its lack of hatchback and dated styling struggled against these offerings and sales were poor.

By now, however, British Leyland was working on an all-new car to replace the Allegro and Maxi during the early 1980s - the LC10 - which would eventually emerge as the Austin Maestro.

British Leyland entered the small hatchback market – pioneered during the 1970s by the likes of the Renault 5 and Volkswagen Polo, with its Metro which was launched in October 1980.

The base models of the slightly larger Triumph Acclaim, the first product of BL's alliance with Honda introduced in 1981 also acted as a substitute for the Allegro until the Maestro launched.

[11] In other respects the car was somewhat underdeveloped, and a number of design flaws plagued the early models, earning it the nickname of the 'All Aggro', which intensified over the next few years as well publicised stories about its build quality and reliability emerged.

Most of these were fixed in the Allegro 2 edition of the car, launched in 1975, by which time a slightly smaller round steering wheel had quietly been substituted for the "quartic" original.

Sales in its final years were disappointing, and by 1981 it had fallen out of the top 10 as more buyers were choosing two newer BL products: the similar-sized and more viable Triumph Acclaim, and the smaller Austin Metro.

ran a feature on the then new Allegro, including an interview with staff at a BL dealership, who were asked if any problems occurred with the car in service.

Clarkson noted that while the Allegro had initially been intended as a forward-looking design to compete with technically advanced European cars such as the Citroën GS, its development budget was only around half that of the much simpler Marina.

In 2007, Sir Digby Jones, in criticising the inefficiencies of the Learning and Skills Council, said, "It is what I call 'the British Leyland model' – you put a lot of money in at the top, and an Austin Allegro comes out at the bottom".

[9] The Allegro is generally considered amongst the most disreputable British Leyland models; some credibility was restored with its replacement the Maestro which was tipped as an adequate competitor to the Ford Escort, Vauxhall Astra and Volkswagen Golf.