The Mk 1 was presented to the public at the London Motor Show in October 1963, and volume sales began in January 1964.

The estate car body shell was partly built by Carbodies,[15]: 119  and in the Mk 1 version was the same length as the saloon.

Various minor improvements were made during the period of which the most noteworthy, probably, was a significant upgrade in October 1966 to the "previously rather ineffective" ventilation, with eyeball vents added in the centre of the facia and the heater controls repositioned beneath them.

In June 1975 the 2500S model, with 14 inch (356 mm) wheels and anti-roll bar, was added: it replaced the 2.5PI which had quietly disappeared from the show rooms two months earlier.

[18] This marked the end of fuel injected engines for the car, but improved acceleration was claimed for the twin carburettor 2500S and its slightly less expensive 2500TC sibling.

[18] These new versions featured an extensive list of other, mostly minor, improvements, of which the most significant were probably those affecting the ride and handling: these resulted from suspension changes including an anti-roll bar.

Six-cylinder 2300 and 2600 versions of the new Rover would nonetheless be powered by engines designed by Triumph, originally intended to replace the older 2000 / 2500 units.

Sir Rob Muldoon, New Zealand's then Prime Minister, privately owned a white 2500S and had been known to drive to work in it.

[23] The 2000 and derivatives are also popular with modifiers owing to common parts and engines shared with other Triumph models such as the TR6, GT6, and Vitesse.