Americans drive a lot more than Europeans, that's probably why. For comparison, I'm in Canada in my mid-20s and only pay CAD$700 per year, same as you (clean record).
You have to specify how many miles per year you're going to drive - that £400 a year insurance is declared for 10k miles. How many more do Americans drive? 20k? 30k? Aren't those very silly numbers quickly? I thought even in America people drive no more than 20-30 miles a day on average, no?
