What 1967 (UK), 1968 (US), TV series had in the opening sequence the hero running across a beach, only to be captured by a big white balloon?

The Prisoner is a 17-episode British television series first broadcast in the United Kingdom from 29 September 1967 to 1 February 1968. Starring and co-created by Patrick McGoohan, it combined spy fiction with elements of science fiction, allegory, and psychological drama.

The series follows a British former secret agent who is abducted and held prisoner in a mysterious coastal village resort, where his captors try to find out why he abruptly resigned from his job. Although sold as a thriller in the mold of the previous series starring McGoohan, Danger Man (1960–68; retitled as Secret Agent in the US), the show's combination of 1960s counter cultural themes and surrealistic setting had a far-reaching effect on science fiction/fantasy programming, and on popular culture in general.