Gay rights champion Leo Abse has died at the age of 91, a family friend said today.
The former Labour MP died at Charing Cross Hospital, west London, last night after a short illness.
Mr Abse guided a Private Member's Bill through Parliament in 1967 that legalised sex between men.
The Welshman was also credited with helping to liberalise divorce laws through the 1969 Divorce Reform Act.
Mr Abse, who was in the Commons for nearly 30 years as MP for Pontypool and then Torfaen, is survived by his second wife Ania.
Wales Secretary Paul Murphy paid tribute to Mr Abse, saying he was "deeply sad" at the news.
"He was a personal friend for well over 40 years," he said.
"He was a very distinguished parliamentarian and social reformer who has left an indelible mark on his country. The lives of millions of people over the years have been improved because of his social reforms.
"Leo was a passionate Welshman and a fine constituency MP for the eastern valley, which he represented in Parliament for nearly 30 years.
"I personally owe him a great debt, and I know that MPs from all sides of the House will mourn his passing."
A solicitor by profession, Mr Abse became a flamboyant figure in Westminster, renowned for his dandyish attire.
He was born in Cardiff, the grandson of Jewish immigrants, and from an early age cultivated a reputation as a troublemaker.
In the 1960s Abse broke the political deadlock over the status of homosexuality with his effective advocacy of the cause.
He persuaded the then home secretary Roy Jenkins to give his Bill Government time, with Labour's large majority ensuring it passed.
He was also heavily involved in easing the restrictions on divorce.
Mr Abse's efforts led Labour prime minister James Callaghan to tell him: "You do much more good in terms of human happiness than 90% of the work done in Parliament on political issues..."
A keen student of psychoanalysis, the father of two published a series of books seemingly designed to scandalise the establishment.
One volume released in 2000 - Fellatio, Masochism, Politics And Love - offered "an analysis of the repressed homosexual components of the relationship between Gordon Brown and Tony Blair.
Former Labour leader Neil Kinnock and his wife Glenys added their voices to the tributes.
"Leo was courageous, highly principled, very funny and totally unique," they said in a statement. "We are glad that he had such a long and fulfilling life in which he gained so much social progress by being an outstanding free-thinking socialist."
Liberal Democrat equalities spokeswoman Lynne Featherstone said: "As a nation we should be grateful for his contribution as a parliamentarian.
"He spearheaded some of the most momentous changes in legislation, paving the way for greater equality.
"His successes in Parliament freed many from the shackles of paternalism and bigotry, allowing us some of the basic liberties we now take for granted.