[Tannaton]

As has been said if a stop lamp is fitted - it’s testable. Additional lamps may be excluded in they aren’t wired up but anything fitted at the factory should be tested, if you disconnect it then technically it should pass but you would have to leave evidence visible to the tester that you have disconnected it. nearly all post 1996 cars have a 3rd brake light. Volvo started fitting them much earlier - my 1989 440 had one.

Where the brake light has “multiple sources” (e.g. led matrix), upto 1/2 of those sources not working is a minor defect (I.e. advisory under the old system). More than 1/2 not working is a major defect I.e. fail.

This is documented in section 4.3.1 of the latest MOT tester manual, I think clan is thinking where there are multiple brake lights in a single light cluster. If you read all the website pages, it contradicts itself several times on this topic...