Hardiman was also known for other roles in shows such as The Crown, Doctor Who and Wallander.

His death was announced "with great sadness" by his agency Scott Marshall Partners, which added he was a "beloved client and much-loved stage and screen actor".

His role in 1996 show The Demon Headmaster - a much-loved CBBC programme based on the books by Gillian Cross - saw him hypnotising his victims while running a school.

Hardiman reprised his role in the 2019 reboot for a cameo appearance.

He was also an established stage actor, and was a member of the Royal Shakespeare Company in the 1970s.

In The Crown he played Doctor Evans in the second season of the show, as well as starring as a former prime minister, Ramsay Macdonald, in Gandi in 1982, alongside Ben Kingsley.

Hardiman also appeared in an episode of Bergerac in 1985, and Minder in 1982, as well as 57 editions of Crown Court and 12 episodes of Secret Army.

The actor was born in 1937 in east London and later studied English at Fitzwilliam College at Cambridge.

He is survived by his wife Rowena and his children.