Weren't the words a poem written by Wordsworth or Rudyard Kipling or some such? I'm sure Dave Fletcher's said that. Can't remember which poet exactly, but the guy wrote it on his travels, when he'd been going through a bout of depression and found himself at the junction of those two rivers. He was so gobsmacked by the sight, he immediately put pen to paper. The tune was added by Martyn, I believe?

Someone will tell me if I've got meself arse-about-face.