It didn't take long for some bright spark to discover bronze which led to them settling down and becoming farmers. This was also when they discovered beer. They then went on to start using iron and got invaded by continental immigrants known as celts.
In about 40AD, some more Europeans known as the Romans invaded. They wanted the Brits to be part of a political and economic union with the rest of Europe, and it helped us build a lot of infrastructure and improved or laws and education. Due to issues in Italy, the English sent it away and the Isles went into the dark ages.
In the north of the island, Scotland became separate and just chilled north of the wall with the wildlings and white walkers.
A new set of European invaders started taking over the Isles and making people follow their laws and speak their language. They were the Anglo-Saxons and spoke Angleish which is what we speaketh this day.
The Scots and Pics up north then combined forces to form the Kingdom of Alba and did their best to not be English, although they didn't mind the Vikings as much.
In 1066 the bloody French decided they should rule England, took over and then ruled us from then on.
After that not much happened except a fat king with too many wives, a Scottish king becoming the king of England and therefore making all the English and Scots British and then some silly people went and had a civil war to get rid of the king only to bring his son back a few years later.
It didn't take too long for The Brits to get too big for their isles so they started invading other places. By the early 20th century they owned almost a quarter of the earth's total land area which they named "the empire on which the sun never sets" although many others called it "those bloody brits, coming over here, marrying our women and taking our jobs".
The empire was accidentally lost due to a few little wars known as the World Wars and Britan then had to face the fact they should have probably been nicer to other countries. Those that didn't get free from the empire tended to be unhappy about it and there were a few troubles about it.
Nowadays it's back to being a small group of islands but it's ok because it's learned from it's past... right?