Renowned conductor Sir Edward Downes and his wife, who died together in an assisted suicide clinic, were devoted to each other, the musician's manager said today.
Paying tribute to 85-year-old Sir Edward and 74-year-old Lady Joan Downes, Jonathan Groves said the couple's decision to end their lives at the Swiss organisation Dignitas was "typically brave and courageous".
The pair, who had been battling serious health problems, died peacefully at the clinic in Zurich on Friday, their family said.
Sir Edward, who worked with the BBC Philharmonic Orchestra and the Royal Opera House, was almost blind and had suffered hearing loss.
Mr Groves, who had known the conductor for 35 years, said: "It was a shock to all his friends and colleagues because it was something he and Joan planned very much within their family.
"None of us were aware this was going to happen until after they had died.
"It was very typical of the way he lived his life. I do not think there is anyone anywhere who has lived his life with more self-determination than Ted (Sir Edward) did.
"The decision that he and Joan made to end their lives in the way they did was a very typically brave and courageous decision.
"They were absolutely devoted to each."
Mr Groves, of management company Ingpen and Williams Ltd, said Lady Downes, a former ballet dancer, had become "very ill" and Sir Edward was suffering the ailments of very old age.
In a statement, their son and daughter, Caractacus and Boudicca, said: "It is with great sadness that we announce the death of our parents Edward and Joan Downes on Friday 10th July.
"After 54 happy years together, they decided to end their own lives rather than continue to struggle with serious health problems.
"They died peacefully and under circumstances of their own choosing, with the help of the Swiss organisation Dignitas, in Zurich.
"Our father, who was 85 years old, almost blind and increasingly deaf, had a long, vigorous and distinguished career as a conductor.
"Our mother, who was 74, started her career as a ballet dancer and subsequently worked as a choreographer and TV producer, before dedicating the last years of her life to working as our father's personal assistant.
"They both lived life to the full and considered themselves to be extremely lucky to have lived such rewarding lives, both professionally and personally.
"Our parents had no religious beliefs and there will be no funeral.
"They will be missed by Caractacus, Boudicca, Omar and Zeki, as well as by many family members and friends."
Sir Edward was born in Birmingham in 1924 and as a young man studied and worked with German conductor Hermann Scherchen.
He went on to work with the BBC Philharmonic Orchestra for 40 years, first as chief guest conductor, then principal conductor and finally conductor emeritus.
Sir Edward joined the Royal Opera House in 1952 and remained a company member for 17 years.
Mr Groves said one of his lasting contributions to British music would be his service to the Royal Opera House, where he conducted in every season for over 50 years, taking part in 49 different operas in 950 performances.
Sir Edward became the music director of the Australian Opera in 1970 and conducted the first performance in the Sydney Opera House.
He received a CBE in 1986 and was knighted in 1991.
A Metropolitan Police spokesman said: "It was reported to police on Monday, July 13, that a man and woman from SE3 had died in Switzerland.
"Following inquiries police are looking into the circumstances of the apparent death of an 85-year-old man and a 74-year-old woman on Friday, July 10, in Switzerland.
"We continue to investigate the circumstances of their deaths. No further details at this stage. The investigation is being led by Greenwich CID."
A controversial move to relax the law on assisted dying was thrown out by the Lords last week.
Peers voted by 194 to 141, a majority of 53, to reject Labour ex-Lord Chancellor Lord Falconer of Thoroton's proposal to allow people to help someone with a terminal illness travel to a country where assisted suicide is legal.
Sarah Wootton, chief executive of campaign group Dignity in Dying, said: "Sir Edward Downes and Lady Joan Downes add their names to the ever growing list of Britons who have travelled abroad to die.
"This problem is clearly not going to go away; we are descending down a slippery slope towards unregulated assisted dying abroad, at a rapid pace.
"This emphasises the need for the safeguards that Lord Falconer was calling for in his amendment to the Coroners and Justice Bill last Tuesday.
"Opponents to the amendment, which was eventually defeated by 194 votes to 141, said that it would turn the traffic lights on assisted dying from red to green.
"The light is already green and what is needed is urgent action to safeguard the practice in this country.
"The amendment clearly does not relax the law - it sets out to regulate the law.
"Dignity in Dying believes that, within safeguards to prevent abuse, people should be able to make such decisions for themselves, but safeguards are the key and without them, as is the situation at present, the process is dangerous and open to abuse."