Pretty Problem

This pretty weed is Himalayan Balsam and can be found along a vast amount of the banks of the River Alne. It is quite an invasive plant and will kill all of the other vegetation around. It was introduced to the UK in 1839, and is now considered to be a problem.
When the seed pods ripen they explode, dispersing their 800 or so seeds over a wide area. 
Some places organise "balsam bashing" events to try and keep it under control, but sadly I think it's too late for the River Alne.