Indian Balsam (Impatiens glandulifera)
Sadly this is another unwelcome arrival from over sees and another case of us paying for the Victorian habit of collecting 'nice things' from the colonies and bringing them home. This plant is something of a pest as it is free growing, spreading rapidly and becoming dominant at the expense of other natural species.
It is not even very good for insects or as a food for any other living thing so it is a flower we could well do without but impossible to eradicate. We put more effort into pulling Ragwort which is far more beneficial, than we do in to controlling this plant.
What the plant does have in its favour is these lovely large pink flowers that give the plant its nick-name, Policeman's Helmet. Ever see a policeman with a pink helmet?