As the title states, roughly how does salary in London compare to a job in the south (say, Bristol), versus a job in the north (say, Leeds)?
The numbers are regional instead of by city, and are mean averages.
For your three areas: London £29,947
Yorkshire (including Leeds I believe) £20,247
South West England (which would include Bristol; but also all of Cornwall) £20,954
A more industry specific query might have significantly different results.
The average salary in London is almost certainly going to be higher, when I was looking for a new job it was anything from 5k-10k higher in London than it was in East Anglia.
Don't be fooled by the higher salary, if I would take pursued a city job I'd be losing several thousand per year on commuting, not to mention time as well. Thats not mentioning relocating closer to the city, that would be more expensive.
You have to weigh it up, is the salary really going to compensate the commute/living costs?