[2] The concept of enlarging the Speed Twin, the Thunderbird name and its 'paper dart' logo were thought up by managing director Edward Turner on one of his regular trips to Triumph's operations in the USA.

The 'paper dart' logo was embossed onto the chain case cover on Thunderbirds from 1955 to 1962 and can be seen upon closer examination on the supplied photograph of the 1962 model.

The 6T Thunderbird was launched publicly at Montlhéry near Paris, where three standard-production bikes were ridden around a circuit by a team of riders who between them averaged a speed of 92 mph (148 km/h) over a distance of 500 miles (800 km).

[3] Triumph obtained further lasting publicity with Marlon Brando's 1953 motion picture The Wild One, in which he rode a 1950 6T Thunderbird.

[6] The Triumph TR65 Thunderbird 650 cc parallel-twin was a short-stroke version of the 750 cc T140 Bonneville engine and was the cheapest model in Triumph's range with budget features such as a drum rather than disc rear brake, the absence of a tachometer, a merged exhaust system, painted rather than polished alloy and economy Dunlop Gold Seal tyres.

NVT passed on the prototype to the Meriden co-operative which also chose not to proceed to production despite experimenting with installing the engine in their oil-bearing frame.

Hinckley also produced an accompanying clothing range consisting of sew-on patches, leather jacket and ankle boots, all featuring Edward Turner's original 'paper-dart' Thunderbird logo.

A 1995 model received great exposure when it featured in publicity photos for the film Barb Wire with its then-high-profile star Pamela Anderson.

In July 2008, Triumph announced the new Thunderbird, a 1,597 cc (97.5 cu in) liquid-cooled parallel-twin cruiser with six gears and belt drive.