As we noted when the price increase was first announced, the reason for the hike is the weakening British pound. Compared to the dollar, the pound is about 17 percent weaker since the Brexit vote took place last summer. It's also about 10 percent weaker than the euro. That's a substantial difference on an electric vehicle that starts at 58,900 pounds.
Costs for all sorts of things have gone up since the Brexit vote, from wine to Toblerone to books to general consumer goods like shampoo, so it's not just EV fans that are feeling the pinch. How a five-percent increase in Model S and X prices across the pond will impact Tesla's UK sales will be interesting to watch in the coming year.