Did Darwin evolve his theory?

The originality of the idea behind one of the great scientific discoveries - Darwin's theory of evolution - has been questioned by a Cardiff academic. Professor Paul Pearson from Cardiff University tracked down the earlier publication by geologist James Hutton in the National Library of Scotland.
The story gives no actual details of what Hutton said (but evidently he didn't say an awful lot, otherwise you would now be reading The Friends of James Hutton website—which doesn't have quite the same ring to it). The original version of the story contained a number of errors, which I got the BBC to amend [More »].