Sense of humour in England

Big question, but I can answer a little of it.

Much of this depends where you are at the time, humour in London being different in subtle ways to humour in Yorkshire, especially Allah's own Barnsley.
Much of England's humour is subtle in ways Americans have no clue about, especially when the English use sarcasm in ways non English people just can't work out. Many jokes have a history behind them so, as Americans don't have any history, this further confuses them in the same way a maggot gets confused with thermonuclear dynamics.
Yorkshire, a place where humour tends to be direct, and a place diplomats don't come from, has a direct form of humour that, whilst not the forced jokes American TV uses, is extremely funny. As the whole world knows, all the best and funniest people come from Yorkshire, most of them from Barnsley.
It's all but impossible to tell a pure Barnsley joke and expect non-Barnsley people to understand it unless the foreigners concerned (foreigners include people from London and America) are fluent in Yorkshire, a language that can take up to 25 years of linguistic study just to understand the vowels.

This also works for the English as wordplay is a notable form of humour

https://youtu.be/kAG39jKi0lI