Until I found out otherwise, I did not know that the voice and the body were of two different people. He was Darth Vader and a road safety guy. With Chewbacca gone, it looks like the biggest actors of the franchise are gone.
He had a role in A Clockwork Orange (at right) and also appeared in Doctor Who. He was the go to guy for UK TV shows that needed a monster or hulking presence.
As the story goes, the notoriously retake-demanding Kubrick made Prowse carry Malcolm McDowell up and down those stairs many, many times.
Prowse was justly rewarded by the universe (presumably) for that patient effort by eventually becoming a sci-fi icon. Condolences to his family, friends, and fans.