MG's famous Midget series of T models ran through TA, TB, TC, TD and TF before the entire series was replaced by the MGA. The 1950 release of the MG TD Midget caused quite a stir. Despite the car looking essentially the same as the TC it replaced, under the skin much was new. The car was five inches longer, and the body four inches wider than the immediate post-war TC which it replaced. Top speed was increased to 80mph from the 1,250cc overhead valve engine. It was the handling that saw the greatest improvements over the TC. The MG TD featured independent front suspension with coil springs, together with rack and pinion steering and 15" disc wheels for the first time. A TC drivetrain with modified hypoid geared rear axle and a completely new chassis developed in the Y-Type saloon and making use of box-section side rails and crossmembers and it was of all-welded construction; this provided a much sturdier and stiffer frame than the old Midget chassis

Styling changes to the MG TD, which was created largely at the Abingdon factory rather than Morris's Cowley design office, over the MG TC include new bumpers front and back and new 15 inch pressed-steel wheels in place of the old 19 inch wire-wheels (although these looked slightly odd on such an old fashioned car and didn't quite manage to fill the arches). Using the traditional steel on a wood-frame construction, the TD's body retained some of the classic T-series lines while updating them ever so slightly. This was a huge leap forward for the company, who were now able to offer the option of left as well as right hand drive, and helped make the new MG TD of 1949 by far the most popular of the Midgets.

1950 saw MG release the MG TD Mk II. With a more highly tuned version of the XPAG engine producing 57bhp at 5500rpm, bigger carburetors and further improvements to the suspension, the MK II furthered the MG TD's sales success.

The MG TD was dropped to make way for the MG TF and MG TF 1500, with the last MG TD being sold by an MG dealer in 1953.