If you’re coming from outside the UK, you’ll need to get some pounds. The easiest trick? Use an ATM at the airport. But don’t let the airport booth rob you with a terrible exchange rate. Instead, take money out of a high-street bank ATM once you’re in central London. Places like Barclays, Lloyds, or HSBC are everywhere. Pro tip: always say “no” when the machine offers to do the conversion for you. That’s how they get you with hidden fees. Let your home bank handle it.
What Is the Currency of London? | Your Guide to Money - GlobalBanks
Another option? Bring some dollars or euros and visit a dedicated exchange bureau in the city. Avoid the ones at tourist spots like Leicester Square—they’re basically vampires. Look for a shop with a “No Commission” sign. Even then, compare rates online first because you are smarter than a cashier.