No idea which ones but some of the Scottish islands had no need for MOT. The smaller ones such as Canna for example did not need mot so long as the vehicle never left the island. Strangely island based lorries but cannot remember the sizes now were allowed no testing and could leave the island for essential journeys. I doubt that still applies tho'.
It's the same here as cars registered on the islands are test exempt and taxed at a very cheap rate but they cannot be driven on the mainland.
On a cycling day trip to Inisheer once, I was trying to work out why someone would need a top of the range V6 Renault Laguna to drive around an island four miles long. I'm sure there must be loads of opportunities to use all that power and luxury!