You can find good roasted coffee of many types in most of these places.
But if you need an espresso or any other Italian styled coffe. Nothing can beat Italy.
I admit one exception: Portugal. In a long trip to Lisbon I’ve done I had some of the best coffee there !
Edit: still using my 18yr old Bialetti for most of my coffee here and buying coffee when going back occasionally (ever brought back a trolley full of coffe through airport security checks?). Only reliable way so far to have decent coffee.
London is i think the original place from where high end coffe culture spread out to europe and where idea of small independent roasters came from.
I often buy coffee from London when i can get it. Square Mile, Has Bean, Union Coffee, Caravan coffee all mostly highest quality stuff.
Funnily enough i've lived in portugal for a while and coffee was so bad i had hard time finding good beans. Luckily some cafes were importing stuff but no roasters.
Look around a bit you can for sure find awesome cafes in London. If not there than probably nowhere. I posted few of my fav London roasteries to comment under this one.