The UK car industry collapsed in the 1970s because the class structure in Britain paid mechanics and labourers low wages. UK designed cars were expensive and higher quality, but labour-intensive. When labour costs rose in the 1970s, it became uneconomic to build and maintain UK designed cars. Labour strikes in the 1970s disrupted production. There has always been somewhere that can make it cheaper, by paying lower wages, then wages rise, and so the car industry moves on. The sequence has been something like: Japan, Taiwan, South Korea, Malaysia, China, India, ...
Beginning in the late 1960s, overseas exports of UK manufactured vehicles were reduced by Japanese competition. That was done using clever accounting principles. The Japanese production lines, built cars for Japan and depreciated the line equipment during the day. At night, Japan built cars for export, without the cost of depreciation. That artificially reduced the cost of cars for export, without it appearing to be dumping.