Penny Service in a dramatised episode of BBC arts programme
Monitor entitled
The Debussy Film. Directed by Ken Russell and starring Oliver Reed.
Name:
https://www.imdb.com/name/nm0785824
Title:
https://www.imdb.com/title/tt0056980/reference
The nudity is water-distorted vague only. When she gets out of the pool (bottom right) it is clear she had had no swimsuit top on.