Great Britain was and is a global super power. A few hundred years back they had the claim to a massive amount of land all over the world.
The first picture represents 1920
Tea is consumed regularly in GB, and it was also the subject of a rebelling of sorts. Britain had sent a shipment of tea to the US, but some Americans threw the tea in the harbour, as to show that they didn’t want to stay under british rule.
The British language can go from comically posh to street slang, depending on where you are. Especially in cities you will hear a lot of slang.
Here’s an example of some slang which can be heard in London, provided that you go to certain areas.
GB and especially England is a class-society, meaning that social classes swing wildly and you will come to see a lot of both extremes if you come there, which is not as common in Denmark.