Dotted Loosestife - http://www.flickr.com/photos/qwertyqwertyqwerty/
The Dotted Loosestrife (Lysimachia punctata) is a species of plant in the Primulaceae family.
This specues is an alien to Britain from southern Europe, but is widespread in Britain now. This erect plant can reach over a metre in height, and has batches of yellow flowers together. The flowers can be seen from summer till autumn.