This is really not a UK-only thing, it's a thing everywhere.

The US has some defense jobs that pay well (but are immoral IMO), and there are some gambling-machine related jobs that pay well, but otherwise engineering pays really poorly.

I used to work as an embedded engineer in Slovenia, in the automotive industry, and wanted to potentially move to Germany or Austria or Switzerland to do something similar. After interviewing with some really prominent companies, household names if you will, and seeing their offers - I bushed up on my CS and switched to finance.