Reference for the UK figures:
www.caa.co.uk/docs/33/RegReview.pdf
1.3 fatal accidents per 100,000 flight hours for the UK:
(over a decade ending in 2004)
As an aside, the really interesting statistic is for gyroplanes - over 40 fatal accidents per 100,000 hours. I think I understand where the naysayers for statistics are coming from, and I know the numbers should also be interpreted with caution due to the relatively small number of aircraft. But I think when you get differences like that, they're trying to tell you something.
1.14 fatal accidents per 100,000 flight hours for the US:
Fact Sheet – General Aviation Safety
(2010 figure)
To be honest, it wasn't hard to find. '1.3 100,000 caa' and '1.14 100,000 faa' in google work fairly well.