Upvote:13
No. Euros are not commonly accepted in the UK, especially for large payments. Some tourist oriented places might accept Euros - those that do are just as likely to accept US dollars. Hotels are likely to have a change facility, but a busy tourist attraction is not going to want to take the time to convert your foreign currency to pounds.
Credit cards are widely accepted, provided you have a chip and PIN card (which you are probably going to need in Europe anyway). A credit card will be much more useful than Euros.