So, what have we learned? London uses the pound sterling (£). Cash is for emergencies, cards are for everything else, and euros are for the airport trash bin.
Remember to call it quid. Tap your phone like a local. And never, ever ask if they accept “dollars.” You’ll get a lecture. Possibly a scone thrown at you. Probably not. But why risk it?
Now, go enjoy London. Spend those pounds on a pint, a pie, or a cheeky souvenir. Your wallet is ready. And so are you. Cheers.