The Vixen-based cars were replaced in the early 70s by the M series. The bodywork was designed by none other than Mike Biglandwho previously John Burtonhad a racing service. Compared to the Vixen, this was a big step forward. It was much cheaper to produce, more durable and better protected the occupants in the event of an accident. Between 1972 and 1980, the car was equipped with several engines. In addition to the 2500M, 3000M, 1600M, Taimar and 3000S models, turbocharged V6 blocks were also produced. During the production of the M series Jacks Pickard also returned to the company. TVR was so confident in their cars that they offered a 5-year guarantee against corrosion. Car exports also increased, with 60% of their cars 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 1977s, 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 XNUMX, TVR management asked Oliver winterbottomto design a new two-seater coupé. Ian Jones, formerly of Lotus Cars, designed the bodywork. The prototype project initially progressed slowly, but was finally road-tested by January 79. The car was powered by a Ford 2.8-litre fuel-injected V6. The car was called Tasmin, a cross between the female name Tamsin and the Australian Tasman racing series. During the development of the car, TVR had no money to pay its suppliers. Its financial problems were further compounded by the fact that at the end of 79, £100.000 worth of M-series cars were seized in the United States because they failed to meet emissions standards. The Tasmin was launched in 1980 and, although much loved by motoring journalists, it 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 thereby handing over the driving seat to a wealthy TVR buyer, Peter Wheelerto.