I think its actually Julie Matthews & Chris While. The song was written by Julie Matthews. Here are the words as Simon Nicol sings them on Fairport's "Jewel in the Crown" CD (my transcription - if there were lyrics with the CD, I've lost 'em).

JEWEL IN THE CROWN
by Julie Matthews

We are a proud land, we stand for freedom,
We've got the franchise - on how to lead them,
We've got the history - books to prove it,
Give us a mountain - and we will move it,
We rule the waves and - the seven seas
We - bring the mighty - to their knees
We - offer hope and – inspiration,
A fine example – to lesser nations,
We are Britannia, the jewel in the crown.

We brought a system – to the masses,
Divide the nation – into classes,
It's in our breeding – and on our faces,
At least we're all born – knowing our places,
We stay within our – social borders,
We only take what – our class affords us,
It doesn't matter – that it's not even,
It's just the nature – of the demon,
We are Britannia, the jewel in the crown.

   We are Britannia, we crowned? an empire,
   We came and conquered, we tore their borders down,
   We need no conscience, God is on our side,
   We are Britannia, the jewel in the crown.

We are your friendly – liberators,
We'll free your country – from your dictators,
For a small slice – of your oil wells,
We'll send our boys in – with their gun shells,
We are a refuge – for the needy,
Always caring – never greedy,
Whatever gesture – could be finer,
We've given Hong Kong – back to China,
We are Britannia, the jewel in the crown.

   We are Britannia, we crowned? an empire,
   We came and conquered, we tore their borders down,
   We need no conscience, God is on our side,
   We are Britannia, the jewel in the crown.