I could be wrong, but I don't think the 25-year import rule in the US has anything to do with what side drive the car is. It was a law passed in the 80s to shut down gray market imported cars. Importers would buy cars from countries where they sold for much cheaper than the US and then resell them for way less than official dealerships.
The law would've been targeting left-hand-drive vehicles, so the right-hand-drive stuff is just a byproduct of it. I mean, the US government had all of its postal service trucks built to be right hand drive.
The issue was also heavily lobbied by Mercedes. It wasn't about profit loss, it was about people importing base and utilitarian Mercedes vehicles. Think cloth seat sedans and offroad unimogs. Mercedes fought this imports in order to uphold their prestige as a luxury manufactuer. They refused to import those things
The dot safety rule is 15 years. Assuming the emissions are the same you could import a right hand at 15 years. You can however order right hand drive cars like jeeps, commercial vans, and other cars used for deliveries.
For sure. I just meant that as we’re part of Europe, had open borders, and are connected to the continent by the Eurostar, is wasn’t at all uncommon to see European cars/number plates on British roads, and the vast majority were right hand drive. I’ve never seen an American number plate however, just as I imagine an American wouldn’t be used to seeing a British or French number plate on a Renault Clio in America, regardless of whether it was LHD or RHD.
Is it illegal to drive a left-hand drive car in the UK?
Not at all. As long as your car is legal in other ways, it’s fine to drive a left-hand drive car here.