Himalayan Balsam (Impatiens glandulifera) flowers in late summer. 

 The flowers are pretty in pink and attract bumblebees.

 Case in point the black centre of the middle flower in the photograph above is in fact the backside of a bumblebee!
 Himalayan Balsam is indeed from the Himalayas and was introduced to the UK by Victorian gardeners who appreciated its qualities as a tall, fast growing annual. However I. glandulifera is no longer appreciated to the extent that it is considered an invasive species by the Wildlife and Countryside Act with certain legal restrictions on its spread.
 If you type its name into a search engine there is no shortage of material explaining how bad it is. But there is another point of view. I would commend to you a 15 minute radio program archived on the BBC website from series one of 'Mabey in the Wild' by the ever illuminating Richard Mabey. The program is entitled 'Indian Balsam' which is an alternate common name. He has some fascinating things to say about the past, present and future of this outlaw plant.