From 1981 to 1982, Beacham featured as a member of the ensemble cast of the BBC series "Tenko", about a group of women prisoners of war held captive by the Japanese after their invasion of Singapore in 1942. Following this, she continued working in theatre and television before landing the lead role in the 13-part ITV drama series "Connie" (1985). Her roles in "Tenko" and "Connie" helped to springboard her into one of her most well-remembered roles, that of the devious matriarch Sable Colby on the television series "The Colbys" (1985–1987). "The Colbys" was a spin-off of the opulent prime-time soap "Dynasty" which had been the highest rating programme in the USA that year. Beacham was cast opposite Charlton Heston as the tent-pole couple of the new show. "The Colbys" never experienced the success of its parent show and was cancelled after two seasons, though in 1988, Beacham was invited to reprise the role of Sable on "Dynasty", playing opposite Joan Collins in a season-long "battle of the bitches" scenario.