Tragedy in British TV ... actor Michael Keating -- best known for his work on "Doctor Who," "Blake’s 7" and "EastEnders" -- has died.

Michael’s agent, Dan Ireson, confirmed the news on Friday ... revealing the actor passed away peacefully at home on April 26. He also shared that Michael had been living with dementia before his death.

His exact cause of death has not been revealed.

Michael carved out a long career on TV... landing his big break in cult sci-fi favorite "Blake’s 7" as Vila Restal before later appearing in the 1977 "Doctor Who" story "The Sun Makers" -- and staying connected to the franchise for years through audio projects.

Soap fans will also know him as Reverend Stevens on "EastEnders" ... where he became a familiar face during a run spanning more than a decade, from 2005 to 2017.

Michael was 79.

RIP