It's not a bank in the UK, though I believe it has a Lithuanian banking licence. It aims to become a bank.

I like the idea of the currency conversion in Revolut but the execution is crap, and I suppose they are never going to make money on it. These days they seem to be more focused on their "crypto" and "trading" offerings, but it is not a genuine trading platform as all you do is suggest a trade to Revolut which they do themselves and then give you a proportion of the gain or charge you the loss.