"Jerusalem" is based on a poem by the famous poet William Blake.
I think "builded" must be old fashioned language, Blake lived in the 18th century.

It goes like this:

And did those feet in ancient time.
Walk upon England's mountains green:
And was the holy Lamb of God,
On England's pleasant pastures seen!

And did the Countenance Divine,
Shine forth upon our clouded hills?
And was Jerusalem builded here,
Among these dark Satanic Mills?

Bring me my Bow of burning gold;
Bring me my Arrows of desire:
Bring me my Spear: O clouds unfold!
Bring me my Chariot of fire!

I will not cease from Mental Fight,
Nor shall my Sword sleep in my hand:
Till we have built Jerusalem,
In England's green and pleasant Land


The expressions "England's green and pleasant land" and "Dark Satanic Mills" are used quite a bit in media for dramatic effect, since they are known from this famous song. "Chariot of fire" is Elijah's chariot from the bible.

The idea from the song that Jesus visited England is a bit of folklore that is part of some popular legends, similar to the Arthurian legends. It is extremely unlikely that this this happened, although England was part of the Roman empire at the time that Jesus lived - and many years of Jesus life were unaccounted for.

Every year in the UK there is a festival in the UK called "The proms". It goes on for a few days and is finished by "The last night of the proms" which is a festival where some famous patriotic hymns are sung. People congregate in parks and squares all around the country and watch the finale from the Royal Albert Hall on large TV screens.
This is the most nationalistic day in the UK which does not have an official national day.
Jerusalem is one of the favourite songs from last night of the prom, together with songs like "Land of Hope and Glory", "Rule Britannia" and "Auld Lang Syne".

I have never like English football If I must watch an English sport, then I like to watch rugby!
The rugby song is "Swing Low, Sweet Chariot".