The whole bay here is called St. Oswald's bay, with the nearer half known as Man O' War Bay, which faces the Man O' War Rocks seen in the sea.
A large cliff fall occurred in 2013, and the rubble is still visible on the shore in the far part of the bay, where the cliffs are stained yellow.
The milky white sea is caused by fine particles of chalk from the rock fall, and it is easy to see the current drawing the chalk out to sea and along the shore towards the viewer.
A closer view of the landslip can be seen in
SY8180 : Landslip at St. Oswald's Bay, near Lulworth, Dorset. The photo also includes some people, giving a sense of the scale of the collapse.