Which is more convenient? Pounds or Euro's when visiting England?
It's not about convenient. It's about what the official currency of the country is. In England...pounds! Euros will not be accepted most places, any ATM will dispense money in pounds, prices are posted in pounds, and the very few places that accept euros (or dollars or canadian dollars) will do so at a ridiculous exchange rate.
Have you done any research? At all?
Be nice folks......