Get euros before coming or not?

You will always get about 2% more for cash if changing money in the UK. There are though much better and safer ways of bringing your spending money.

You can use a UK credit or debit card almost everywhere, except most taxis, some bars and smaller shops. The contactless limit here is €50.

If you withdraw cash as required from ATMs you get the commercial rate, not the tourist rate.

ALWAYS decline the offer of a local currency conversion. Pay in Euros and let your bank apply the conversion.

Tesco`s are having a `sale` until Sep 5 ..

You will therefore get near perfect rates on purchases and you can withdraw cash at ATMs at the same rates. When you do this you must only use MB Multibanco ATMs, these are pink ones, there are 2 in the Old Town Square outside Millenium bank next door to the Ice Cream parlour. They are also in the supermarkets Pingo Doce and outside Continente. When withdrawing, as Cubsur says always refuse their conversion which will be 10% lower. Then if you have online banking, you can pay off the card the following day when it will be shown as a pending transaction, this way you can also pay no fees for cash withdrawals. If you don't pay it off interest will be charged on your next card statement.

Don't use any other ATMs, blue and yellow ATM Euronet and Green ATM Eurozone both charge a fixed fee per transaction which can be very high as a percentage when withdrawing small amounts.

There are also more modern cards Revolut and Mondo with similar benefits but you will need an app for them.