The Vixen-based cars were replaced in the early 70s by the M series. The bodywork was designed by Mike Bigland , who had previously been John Burton 's racing mechanic. It was a major improvement over the Vixen. It was much cheaper to produce, more durable and offered better protection for the occupants in the event of an accident. Between 1972 and 1980, the car was fitted with a variety of engines. In addition to the 2500M, 3000M, 1600M, Taimar and 3000S models, the V6 was also turbocharged. Jack Pickard also returned to the company during the production of the M series. TVR was so confident in their cars that they gave a 5-year guarantee against corrosion. The number of car exports has also increased, considering that 60% of their cars were sold in Europe and the United States.

On January 1975, 200.000, a fire broke out at the TVR factory. Many finished and nearly finished cars were destroyed. Virtually everything was covered in ash. The damage caused was estimated at £150. After the dust and ash that covered everything was cleared, the walls were sandblasted. Only 20 cars were produced that year, of which only XNUMX made it to the USA.

By the end of the 1970s, TVR felt they needed to break away from their previous design. They needed to produce a car that would meet emissions standards, be economical to produce and be a successor to the M series. In August 1977, TVR management asked Oliver Winterbottom to design a new two-seater coupé. Ian Jones, formerly of Lotus Cars, designed the bodywork. The prototype project was slow at first, but by January 1979 it was finally road-tested. The car was powered by a Ford 2.8-litre fuel-injected V6. The car was named Tasmin, a cross between the female name Tamsin and the Australian Tasman racing series. During the development of the car, TVR did not have the money to pay its suppliers. Financial problems were further compounded by the fact that in late 1979 £100.000 worth of M-series cars were seized in the United States for failing to meet emissions standards. The Tasmin was launched in 1980 and, although much loved by motoring journalists, was not a success due to its high price and questionable design. The car's disappointing sales figures once again brought TVR to the brink of bankruptcy. Martin Lilley handed over the reins to a wealthy TVR buyer, Peter Wheeler.