HMRC is the UK government office that collects taxes. The letters stand for His Majesty’s Revenue and Customs — or Her Majesty’s, in anything written while the queen was on the throne. Revenue is the money the state takes in; Customs is the tax on things that come into the country. If you work in Britain, this is who your employer pays tax to, and who you write to about a tax return. People sometimes just call it “the taxman”, though actually it is a huge department, not one man, and it does more than income tax: national insurance, some benefits, and goods at the border sit in the same building, on paper. It was formed when two older offices — Inland Revenue and Customs and Excise — were joined together. It is the British cousin of Taiwan’s tax offices plus customs, not the American IRS. You will see the letters on official letters, on UK tax websites, and in news about money the government is owed.