I KNOW I wrote about the ill-fated Triumph TR7 only last month, but I make no apologies for returning to this fascinating motor car.

As Triumph’s last model, and British Leyland’s last two-seater sports car, the fate of the TR7 has been endlessly analysed by historians looking for reasons why it failed.

The accepted wisdom is that the car was born at a time when BL was flirting with bankruptcy, that its design was rushed, the early cars were terrible and poor marketing decisions meant it never reached its true potential.

Above all, the infamous manufacturing plant at Speke, in Liverpool, is blamed for the atrocious quality of those early cars and the industrial unrest which meant BL never built enough TR7s to turn a decent profit.

But is that really what happened or were the workers at Speke a convenient scapegoat for management mistakes and industrial sabotage?

A new book, written by noted motoring historian Steve Jackson, argues that the Speke plant was a victim of internal politics and bad decision-making.

Prior to the introduction of the TR7, Speke, which built body shells for the Dolomite, Vitesse and TR6, had one of BL’s best industrial relations records. It was also one of the group’s most modern plants and was the only BL site where a car could be assembled, painted and trimmed in one place (thus eliminating the incredibly wasteful practice of ferrying bits and pieces to disparate factories all over the country and assembling them rather like a giant game of pass-the-parcel).

But as Triumph’s range shrank in the 1970s the Speke plant found itself hopelessly under-capacity. In 1976, the factory built 27,657 cars – but it could have made 100,000.

To achieve this, management committed to build a family of models spun off the TR7, including a 16-valve Sprint, a 2+2 hatchback called the Lynx and the high power TR8. When BL’s new boss, Michael Edwardes, cancelled the Lynx and the Sprint (in what many people believe was nothing more than a fit of pique) he effectively sounded the death knell for the Speke plant.

Steve Jackson’s new book – TR7: The Bullet That Backfired on British Leyland – reveals other fascinating stories about Speke, including the possibility that inter-company rivalry led to industrial sabotage. When some of the engines built at BL’s Canley plant arrived for fitting they were found to be sub-standard. Some even arrived without pistons, forcing Speke management to introduce a ‘spin test’ to make sure the engine actually turned over before it was fitted to the body shell. Some suspected this was a deliberate attempt to sabotage Speke’s productivity.

There were other problems, too. Constant specification changes (the result of US safety and emissions laws) left the TR7 in a state of flux in the early years. Management didn’t even have a definitive wiring diagram for the car and more than 3,000 alterations were made after production began.

The American launch – so crucial to the TR’s success – was a disaster. Management refused to move the on-sale date, so the first cars shipped to the US for the press were hand-built. They arrived so riddled with problems that not one of them was fit for purpose. The US importer had to call in its own team to make them driveable. Of the 34 cars shipped to the States for the launch only 17 could be salvaged.

Of course, industrial problems – a shift to different working patterns and enmity between staff and management – did play their part in Speke’s eventual demise but, after reading Steve’s book, it is apparent that there were two sides to the TR7 story, and one did not get a fair airing.

Packed with rare photos, Steve’s book details the whole story behind the TR7, including its rather more successful motorsport record and a look at the TR scene today. It’s a must-have read if you are a Triumph fan and a great addition for anyone with even a passing interest in the British motor industry.

• TR7: The Bullet That Backfired on British Leyland, by Steve Jackson, is published by Lily Publications and costs £16.95. It is available from all the usual websites and direct from the publisher at lilypublications.co.uk/product/tr7/