The horrible mucky pink Primrose is just a cross between the ones sold as Primulas and our native Primula. P. scotica is very difficult to grow. It is thought to be semi-parasitic on dwarf grasses which it grows amongst in its native Scotland.
As with Spanish Bluebells and the native English Bluebells, our native Primula vulgaris is in danger of losing its purity by crossing with the garden varieties. Even Primula veris has been know to cross with these, so you get pink flowers on a tall stem.