I remember my dad singing this when I was very small - I suspect it may have been a Flanders and Swann number. I've googled it and only come with up sheet music to buy, which since I can remember the tune is a tad superfluous! Are there any kind people out there who can remember the words?

I think it started

'Christmas is i-come
Mark ye robin's ruddy tum...'

and there my memory gives out.

Thanks in advance

Chris