Sir Edward Downes was appointed CBE in 1986 and knighted in 1991
Renowned British conductor Sir Edward Thomas Downes, CBE, has died at the age of 85, after travelling to the assisted suicide group Dignitas with his wife.
He and his 74-year-old wife Joan, who was terminally ill, chose to end their lives through the Swiss organisation, their family said in a statement.
According to the statement, the couple "died peacefully, and under circumstances of their own choosing".
Sir Edward had a 40-year relationship with the BBC Philharmonic Orchestra.
"Our father, who was 85 years old, almost blind and increasingly deaf, had a long, vigorous and distinguished career as a conductor," his family said.
Sir Edward and Lady Downes had been together for 54 years
"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.
"After 54 happy years together, they decided to end their own lives rather than continue to struggle with serious health problems."
A Metropolitan Police spokesman said their deaths were being investigated by Greenwich CID, as assisted suicide is illegal in Britain under the Suicide Act.
At least 115 people from the UK have gone to Switzerland to die but, as yet, no-one has been prosecuted.
Born in Birmingham on 17 June 1924, the world-famous conductor began playing the violin at the age of five.
His pursuit of conducting was aided by a two-year scholarship in Aberdeen, which led him to study with eminent German conductor Hermann Scherchen.
In 1952 he joined the Royal Opera where he remained a company member for 17 years.
He became Associate Music Director in 1991 and conducted a huge repertoire at Covent Garden for over 50 consecutive seasons.
He began his relationship with the BBC Philharmonic as Chief Guest Conductor, going to become Principal Conductor from 1980 to 1991 and later Conductor Emeritus.
In 1970 he became Music Director of the Australian Opera and conducted the first performance in the Sydney Opera House.
He was Chief Conductor of the Netherlands Radio Orchestra until 1983 and travelled widely as a guest conductor to opera houses and orchestras all over the world.
Sir Edward was honoured by four music colleges and five universities as well as receiving the Laurence Olivier, Evening Standard, Critics Circle and Royal Philharmonic Society awards.
He became a CBE in 1986 and was knighted in 1991.