there are plenty of UK-based IT staff working for the big banks. There probably are fewer than there once were but there definitely are quite a few still.
There are, but we mostly work in what the bank would term "important functions", so, not retail banking.
Don't shoot the messenger, because as a retail bank customer myself, it pisses me off to, but the money isn't made in retail so its a cost to be managed.
Biting the hand that feeds IT
