This is bullshit. The production process of something as complicated as a car is complex enough that, in order to compete, you need access to the exact lay out and practice of someone who's already doing it OR the time and capital necessary to experiment for an extended period of time. Just being able to make some of the feeder components doesn't give you all the other information capital you need, nor the physical capital necessary to do it with.
Hrrrm, well, if you have factories producing auto parts which are assembled in Britain, (which inherently presumes a certain modularity, since they aren't making whole autos but putting them together from peices), it's not going to take long for some enterprising Indian to import a couple of those British autos, take them apart, and realize he can put the parts together in Lahore instead of Liverpool. Even if the going is slow at first due to lack of expertise, it is probably much cheaper to assemble parts in India rather than transport parts from India, to Britain, and back to India.