A Balsam Hunt

I went out today along the River Kent looking for Himalayan Balsam to pull up. You can see one of our group in the river pulling a few at the edge. She tells me that 5 years ago the river banks were 90% balsam but with concentrated pulling, the river bank is nearly balsam free. There  is another pink flower that now grows profusely on the bank that is not dissimilar to balsam (see extra), but its native, the bees love it and it can stay. I wonder what it is?  I'm tagging this Flower Friday( thanks Biker Bear)  in celebration of finding so few balsam flowers and lots of the unidentified pink flower instead.