Hi, everybody

There are four nations in UK: England, Scotland, Wales and Ireland. People often refer to Britain by another name, they call it "England". But this is not strictly correct, and it can make some people angry, because England is only one of the four nations of the British Isles.
Their political unification was a gradual process that took several hundred years. It was completed in 1800 when the Irish Parliament was joined with the Parliament for England, Scotland and Wales in Westminster.
There are some distinct from each other in almost every aspect of life. In the first place, they were different racially. The people in Ireland, Wales and highland Scotland belonged to the Celtic race; those in England and lowland Scotland were mainly of Germanic origin. And the other hands, for example, the people in Ireland, Wales and highland Scotland belonged to the Celtic race; those in England and lowland Scotland were mainly of Germanic origin. This difference was reflected in the languages they spoke.

Religion: Majority of the people in United Kingdom follow Christianity; most of whom are Protestant Christians. While in United Kingdom, you will come across a number of world-famous churches and cathedrals. Other communities in UK are Roman Catholics, Jews, Hindus, Muslims and Buddhists.

Festivals and Events: A number of festivals celebrated in United Kingdom are centuries old. Major festivals in UK are Christmas, Easter, Thanksgiving and Halloween. Christmas is celebrated not only in the United Kingdom, but all over the world.
Consequently, there are three difference between with four nations: Religion, Festivals and Events and language.

http://www.buzzle.com/articles/culture-of-united-kingdom.html
http://rapidsteps.com/en/en/topic/109/Britain%3A+the+four+nations