1. Pay in general is lower in the UK than the US. The bank will pay what they can get away with and there isn’t enough competition between banks/consultancies/tech/law to drive pay up. I wouldn’t be surprised if more competitive candidates got higher offers.
2. A lot of compensation can be made up in bonuses, though I don’t know what kind of bonus a junior analyst might get.
Minimum wage is £8.72 / hour.
So at a bare minimum (before perks / generous pension / very generous bonus) they are getting three times the minimum wage.
That's still not great, but they are suffering far less than millions of cleaners and other essential workers, not to mention the millions of people on zero hour contracts who are unable to get minimum wage and the thousands of people in forced labour conditions aka slavery (ie migrant Labour).
Which is mostly to say that the condition of most people is a lot lot worse than most of us stop to think about most of the time.