The British actor, who also appeared in U.K. TV shows Coronation Street, Torchwood and Heartbeat passed away on Wednesday (13Apr16) from heart failure.

A message on the Blake's 7 website announcing his death read, "It is with deep sadness that we have to announce that Gareth Thomas passed away this morning, 13th April 2016, from heart failure. Our thoughts are with his wife Linda, and his family and friends."

Gareth played Roj Blake in the science-fiction series, a political dissident who leads a gang of rebels against an international space federation.

First airing from 1978-81, the series developed a cult following and has regularly been voted by science-fiction fans to be among their favourite shows within the genre of all time. At its peak it was watched by an estimated 10 million people in the U.K. and was sold to 40 countries around the world.

However the Welsh-born star insisted his character, Blake, was killed off after two series, a move which dismayed fans. He did however return for its finale.

In addition to his TV career, Gareth was an acclaimed stage actor, appearing in numerous Royal Shakespeare Company (RSC) productions including King Lear, Henry V and Twelfth Night.

Ruth Mitchell, an actress who appeared with him in the play Rutherford and Son in Salisbury in 2001, paid tribute to him on Twitter, writing, "Gareth Thomas played my dad in #Rutherford&Son @salisburyplay our characters hated each other but he was a lovely actor and a lovely man RIP."

In 2012 he returned to his most famous role for a radio series titled Blake's 7: The Liberator Chronicles, while his final stage appearance came in 2013 as Brother Cadfael in an adaptation of The Virgin in the Ice.