Well I'm not a Brit (but I married one).  Let me nevertheless suggest: The Jethro Tull Christmas Album.
 
Gets my vote for best Christmas album ever ... and it's in serious contention for best Jethro Tull album ever.

Best thing Sting ever did - 'Christmas at Sea' - http://www.youtube.com/watch?v=lxZNTZhloiQ

"Bouree" and "A Christmas Song" are on that Tull Christmas album.  

"Out In The Snow"  Al Stewart

"Silently Falling" from Chris Squire's Fish Out Of Water album isn't folk, but it fits.  

"Hard, Hard Winter"--The Strawbs

"Fairy Tale Of New York"--Kirsty MacColl & The Pogues.  Careful, this one has a bit of language that some my find objectionable.  

"I Believe In Father Christmas"--Greg Lake/ELP or the version by Bapu.  

Hi,

Wow ... 

I have a large selection of the folkie-folks like Pentangle, Incredible String Band, Fairport Convention, (only one) Steeleye Span and was looking to get some Planxty, Chieftains and a few more, and was looking for a better and more complete listing.
 
Mostly, I was looking for albums, not just one song, but it's all good, either way.

ampfixer


Did Richard Thompson make a Christmas record?

I can't think of any. Christmas is a bit to cheerful for RT.
 
Seaching on his "Song-o-Matic" page on his website for keywords, Christmas, Winter, Yule only brings up Chelsea Morning, Boom Town and Chuck Berry's Sweet Little Rock and Roller, none of which are particulary Christmassey.

 
Mike Oldfield - In Dulci Jublio

Moshkiae



 
Mostly, I was looking for albums, not just one song, but it's all good, either way.

Kate Rusby's Christmas album 'Sweet Bells' is excellent stuff Pedro.