> but must accept legal tender in certain circumstances.

That's not what legal tender means in the UK and the misunderstanding causes some problems.

If I have a debt, and I attempt to pay in legal tender, and my creditor refuses to take it, I can say I've discharged the debt.

It has no use, in the UK, when I'm buying stuff in a shop.

http://edu.bankofengland.co.uk/knowledgebank/what-is-legal-t...