Lots of threads on this. One thing to consider: Try to go with a bank that does NOT charge Foreign Transaction fees for credit card purchases made outside UK or home country.
In the US we have banks that DO and DO NOT charge these fees. Debit cards also charge fees. I use a Debit card to get CASH out of cash machines abroad and credit cards when possible for everything else. Almost always some sort of fee for this on Debit Cards. Take LARGE amounts of cash as most Debit fees are PER transaction ... whether 20 Euros or 200 Euros ... fee is the same. So big withdrawals cost you less.
Always bring more than ONE card ... preferably two Debit cards and two Credit Cards. All from different banks. Many times, for whatever reason, your card will not work. At the next machine it may work. Or, switch to your other card ... and it works.
Also, before departure, call your banks and advise them you will be traveling and tell them NOT to block your cards when they see foreign transactions. This is a common reason for travelers cards NOT WORKING! CALL the bank.
Even doing this, I've had my cards blocked ... and yet another reason to carry more than ONE card. Many carry three or four.
YMMV, IMHO ...