Why are salaries so low in the UK relative to other more developed parts of the world?

That’s it, that’s my entire Q.

I currently live in Canada and work as a coordinator for the municipal govt and get paid $77k a year but my union is in negotiations right now and it looks like we are getting 15% -/+ a percentage point increase over the next few years. I’d like to move home to the UK as I miss it but a coordinator role the comparable makes £25-30k which is a joke and is the same as when I left, 20 years ago. Why haven’t wages increased when house prices and food have.

Edit. I meant western but my brain failed me this morning. I realize “developed” was completely wrong, I was thinking of dystopian countries rather than implying they are in anyway better.