Canal side wild flower

While on a walk alongside the Kennet and Avon canal in Berkshire a few days ago, I saw this colourful plant growing in patches near the water's edge.
Would love to know what it is.

 

Looks like Impatiens capensis

http://en.wikipedia.org/wiki/Impatiens_capensis

 

That's the one, we have them growing by our canal here too, quite a rare find. Much nicer and more delicate than its thug of a cousin the Himalayan Balsam...

 

Thanks for the info Aesculus and Bilbo.
This is a new one to me, I see it's another foreign import which has naturalised here.
It certainly provided a welcome splash of Autumn colour alonside the canal.