I can't speak too much about the history because I'm American, and have no true understanding. I can tell you it's a song of imperialist oppression, and a powerful video. Lyrics:

Nothin' for us in Belfast
The Pound so old it's a pity
OK, there's the Trident in Bangor
Then walk back to the city
We ain't got nothin' but they don't really care
They don't even know you know
Just want our money
And we can take it or leave it
What we need is

(Chorus)
An Alternative Ulster
Grab it change it it's yours
Get an Alternative Ulster
Ignore the bores and their laws
Get an Alternative Ulster
Be an anti-security force
Alter your native Ulster
Alter your native land

Take a look where you're livin'
You got the Army on your street
And the RUC dog of repression
Is barking at your feet
Is this the kind of place you wanna live?
Is this were you wanna be?
Is this the only life we're gonna have?
What we need is

(Chorus)

They say they're a part of you
But that's not true you know
They say they've got control of you
And that's a lie you know
They say you will never be

Free free free

Get an Alternative Ulster
Get an Alternative Ulster
Get an Alternative Ulster