https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/195074/CONT071791.pdf Page 4/ Wipers/washers: Operate to give the driver a clear view ahead. Rear Wipers are not mentioned anywhere.
No my car passed 3 years running at 3 different MOT stations and the rear wiper had never worked at any of them. If you want to be certain just take the wiper blade off altogether. You can't test what is not there and rear wipers are not compulsory.
I should add that the wiper was there but it had never worked all the time I had the car (5 years) the MOT tester said it was not part of the test as it does not affect the roadworthiness. But some MOT testers will do anything to get some cash out of you for unneeded repairs so best to just take it off before the test.
Be careful the rules haven't been amended recently. In Northern Ireland the Rule is now"if it's fitted it must work". My car recently failed because the headlamp washers only worked on one side.
By the way same applies to a spare tyre , if it is dodgy then just take it out of the car before the test , it is not compulsory to have one but unlike a rear wiper it does affect roadworthiness so if in doubt take it out .
Suspect Vulcan is right and it would follow that a rear wiper has to function. NI is part of Britain after all, and there's no obvious reason why MOT test rules should differ. The rules are updated from time to time. Unhelpfully the VOSA site doesn't tell you for what; you have download the various changes to find out what they say.
I had a Skoda on which the anti-skid braking system packed up. The car had perfect normal braking. The tester said that was irrelevant, when I argued that plenty of cars didn't have it!
Yes, FF, NI is not part of Great Britain. Was thinking that when we say simply 'Britain', as I put, we mean the United Kingdom of Great Britain and Northern Ireland, not Great Britain alone.
The rear wash wiper is NOT currently part of the MOT test. the rear wiper has not worked on my wife's corsa for 7 years and car has never been failed on it. Also one year the spare tyre was below minimum tread depth and when I asked the garage about it - they said the spare is not part of the MOT.