Lord Rix, the master of West End farce who went on to become a leading campaigner for people with learning difficulties, has died. He was 92.

Mencap, the charity of which he remained president until his death, said the one-time actor-manager beloved by theatregoers died on Saturday morning.

(Samantha Pearce/PA)

The peer, who knew he was suffering from a terminal illness, recently wrote to the Speaker of the House of Lords, Baroness D’Souza to appeal for a change in the law to legalise assisted dying so he could “slip away peacefully”.

Mencap chief executive Jan Tregelles said: “Lord Rix was a beloved colleague and friend to so many people with a learning disability and their families.

“His unique charm, personality and passion have been invaluable in helping Mencap grow into the UK ‘s leading learning disability charity, and with his passing the charity has lost a very dear friend.”

(Jim James/PA)

Once a fixture in the West End appearing in innumerable Whitehall farces, Lord Rix was a tireless champion of people with learning disabilities after his eldest child, Shelley, was born with Down’s Syndrome.

After becoming a life peer in 1992, he spoke regularly in the Lords on the issue, voicing his frustration that he was unable to do more for his daughter who died in 2005.

Brian Rix was born into a wealthy Yorkshire family in 1924, the son of a successful shipowner father and a mother who was a producer of amateur dramatics.

Lord Rix with Prime Minister Gordon Brown (Lewis Whyld/PA)

He joined a touring company as a trainee actor at 18 and made his first West End appearance in Twelfth Night in 1943, but his burgeoning theatrical career was disrupted by the Second World War in which he saw service in the RAF and down the mines as one of the Bevin Boys.

After the war he formed his own repertory company, serving his apprenticeship in Ilkley, Bridlington and Margate before taking Reluctant Heroes, one of his early productions, to the London’s Whitehall Theatre in 1950 – the start of a brilliant association which was to last for nearly three decades.

Brian Rix, Stephanie Voss, and Rix’s real-life wife Elspet Gray in A Spot of Bother at the Alexandra Theatre in Birmingham (PA)

His shows, featuring the likes of Tommy Cooper and Sid James, were hits on stage and television, while he earned a reputation for his trousers always falling down.

He became increasingly involved in campaigning for people with learning disabilities and in 1980 he became secretary general of Mencap, going on to become the organisation’s chairman in 1988.

He was made a CBE in 1977, followed by a knighthood in 1986 and a life peerage in 1992, sitting in the Lords as a cross-bencher.