Our CAR OF THE MONTH for May 2009 is the MGB

An early tree-bearing MGB on rare disc wheels. the styling was influenced by Pininfarina.

The MG is still one of the most numerically successful sports cars ever built, with more than half a million made between 1962 and its demise in 1980. At the height of its popularity, Abingdon was making more than 50,000 a year.

The main difference between the MGB and its forebear, the A, was in construction; gone was the rugged and heavy separate chassis, replaced by a light unit construction shell. The car appeared originally as an open roadster, with a three-bearing version of the venerable B Series 1798 four-cylinder engine. Torque was its main strong point - 110lb/ft (149.6Nm) at 3000rpm - but on twin SU carburettors its 95bhp at 5400rpm was creditable, if unsensational. Suspension, steering and rear axle cam straight from the BMC parts bin to keep costs down, so there were few technical highlights, but the B was a genuine 100mph (150kph) car with safe, if uninspired, handling.

It was joined in 1965 by the Pininfarina-inspired B GT, with its tail-gate rear doors and occasional rear seat - strictly for children. It was 160lb (72.7kg) heavier than the roadster, but had the fie-bearing engine and quieter rear axle from the start.

1967 MGB GT

In 1974, MG announced the black bumper cars with grotesque plastic bumpers and increased ride height to keep the aging model legal in North America, where most production will went. Performance was in decline - the GT wouldn't even manage 100mph - and the handling was ruined by its new, taller stance, but the car continued to sell because it was one of few open cars available.

There were two rather more exciting versions of this evergreen sports car to come.

The MGC of 1967 was a three-litre version of the B, designed to take the place of the "Big" Healey 3000 models. Bigger 15-inchwheels and a bonnet bulge differentiated the C from the B and, underneath, thee was torsion-bar front suspension rather than wishbones. With a 145bhp six-cylinder engine, the C was certainly fast, but nose-heavy weight distribution spoiled the handling.

Four years later, British Leyland answered calls for a more powerful version of the car with the GT V-eight. With its smooth, quiet and very torquey Rover 3.5 V-eight this was a much better prospect, but yet again success eluded this 125mph (201kph) machine. It didn't look different enough from the stock four-cylinder car, and the critics panned its lack of suspension refinement, the wind noise and its relatively high price.

Few wanted the V-eight in its day - only 2,591 were sold between 1973 and 1976 - but today it is a sought-after and entertaining classic, easily the best B of the lot.