I too work for the UK govt in the NHS (as a developer), and often wonder if I'm being stupid working for half the pay of my other developer friends. Some of my developer friends work for hedge funds and investment banks and make quite literally 4x what I do. It's upsetting knowing that they will be able to buy a home in London and retire early for enriching some of the worst people on the planet, whilst I will likely have to leave London for somewhere cheaper soon, and will work until I'm 65+. (The NHS pension is quite generous to be fair.)
I get to log off every day feeling good though, so it all seems worth it to me.