Flow-line production technology did not receive widespread acclaim and application in the United Kingdom following the introduction of Henry Ford's revolutionary process in the USA in 1913. This was largely owing to the fact that UK society was then divided into a small number of 'haves', who owned most of the wealth, and a huge number of 'have nots', who could only afford the base necessities of life, plus a small number of middle class. This was unlike the USA, which was a more equal society, so the circumstances were right in the USA to expand car production in the knowledge that there was a huge middle class ready to purchase these cheaper mass-produced automobiles.
In the UK, the upper classes would certainly not want anything that was mass produced and the middle classes were a relatively small market, whereas the large numbers of working class would not have been able to afford to run a car even if it was given free. Ford did, however, produce a number of Model 'T' cars at Trafford Park, Manchester, but these were not principally for UK consumption.
The Second World War in 1939 was the trigger for the widespread adoption of flow production in the UK because as men were called up for war service it meant that women were drafted into factories which had switched over to the manufacture of war products. As women were basically unskilled and war products were needed desperately, flow-line production technology was the ideal solution.