The learning disability charity Mencap has paid tribute to Lord Rix, the charity’s president, who passed away on Saturday aged 92.
The charity said the former actor had played a central role in its history, having previously served as secretary general and chair.
Lord Brian Rix announced he was terminally ill earlier this month in a letter to Baroness D’Souza, the Speaker of the House of Lords, in which he called for euthanasia to be legalised so that people in his situation could die peacefully.
A spokeswoman for Mencap said Lord Rix’s death, which took place on Saturday morning, was due to natural causes and members of his family were waiting for the death certificate.
Born on 27 January 1924, Rix made his name as an actor and producer specialising in farce. Between 1947 and 1977, he produced and starred in a series of successful plays for stage and television, which became known as the "Whitehall farces" after the Whitehall Theatre, where his theatre company was based.
He began using his fame to campaign for disability rights after his first daughter, Shelley, was born with Down’s syndrome in 1951. He and his wife Elspet were told to send her away and forget about her by medical professionals at the time, but they refused and instead began fighting to improve the support available to people with learning difficulties and their families.
In 1977 Rix retired from performance and devoted himself to campaigning, becoming Mencap secretary general, the equivalent of chief executive, in 1980, chair in 1988 and president 10 years later.
He was made a crossbench life peer in 1992 and lobbied for local government to provide respite breaks for carers of children with learning disabilities, which became law in 2006.
Jan Tregelles, chief executive of Mencap, said the charity was "deeply saddened" by his death, and described him as "a beloved colleague and friend to so many people with learning disabilities and their families.
"His passion, zeal and humour will be sorely missed.
"His tireless campaigning has perhaps done more to improve the lives of people with learning disabilities than any other.
"He has played a central role in many of the landmark moments for people with learning disabilities in recent decades.
"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."
Derek Lewis, Mencap’s chair, said those with learning disabilities and their families owed an immense debt to Lord Rix.
Rix’s work had brought about vastly improved life opportunities for those with learning disabilities compared with the situation when his daughter was born, he said.
Lewis said: "He will be greatly missed, but his extraordinary achievements leave us all with the inspiration to continue his vital work."
Both expressed sympathy for his family.
Rix had previously opposed euthanasia, voting against the 2006 Assisted Dying Bill on the grounds that people with learning difficulties could be pressured into euthanasia.
Sarah Wootton, chief executive of the pro-euthanasia charity Dignity in Dying, said: "I sincerely hope that politicians take heed of Lord Rix’s words – that this issue be brought back onto the political agenda, and that the rights of terminally ill people to have choice and control over their deaths do not compromise the rights of disabled people to safety and protection during their lives."
A fundraising page has been set up for anyone who wishes to donate in memory of Lord Rix, at https://www.mencap.org.uk/lordrix.