This flower is an orchid, the leaves are spotted and it is widespread so I suppose common spotted orchid (Dactylorhiza fuchsii) is an appropriate name for it. I cannot help thinking, though, that calling something as lovely as this 'common' rather devalues it. This is by far the most frequently encountered orchid in Dorset, a county with a good number of orchid species. It can be found growing in woods, on chalk grassland, on the heath, on the sea cliffs and in other scrubby areas.
Like many orchid species it comes in so many variations depending on its environment and it hybridises with some other species, mainly the marsh orchids, that the presence of spots on the leaves of common spotted orchids can be very confusing and misleading. The flowers can vary from very pale pink (almost white) to a much more intense colour, especially in damper areas. Allthough other orchids have spotted leaves in summer the spotted leaves are a pretty definite diagnostic feature of this the common spotted orchid as the other spotted leaved orchids are primarily spring flowering. The flower heads can be short spikes and sometimes quite substantial spikes, again I think that depends on moisture and nutrients.
If you want to see common spotted orchids at their best and in some profusion I suggest Durlston is a great place to find them.