US Tax Accountant London: What Americans Living Abroad Actually Need to Know If you're an American living in London — whether you moved for work, love, or just a change of scenery — you probably already know that the US doesn't let you off the hook just because you crossed the Atlantic. The IRS taxes are based on citizenship, not residency. That means even if you've been paying UK tax on every pound you earn, you still have an obligation to file a US return...