Somebody please tell me that the U.S. and Britain are prepared for this

Let me tell it to you. Since mid 2003 Iran has accepted other currencies than petrodollars. Its EU customers have since then payed mostly with Euros. 2003 is long ago, so they must have been prepared for this act.

I don't see why this should affect Britain that belongs to the EU. But it may affect China that has most of its reserves in dollars and would love to spend them in Iran.

Wolfgang