https://www.ukmotorists.com/tinted%20windows.asp"
Why are tinted windows not included in the MOT test? Excessively tinted glass is seen as a serious issue but one which currently affects only a small number of the 24 million vehicles tested annually. To include this item in the MOT test would require all 18,000 garages to incur expenditure on special test equipment and the time taken to carry out an MOT would increase. The MOT fee would have to be raised to cover the extra time and investment.
This extra cost would affect all motorists - all for a small number of vehicles. With the current levels of offending, roadside enforcement is a better route as it targets the offenders while minimising the cost and inconvenience to compliant road users. "