ABBA are mourning the loss of their former sound engineer Michael B Tretow

Benny said in a statement: "You meant more to us four in ABBA than anyone else. I hope and believe that you felt it throughout all the years that have passed since we worked (and continuously laughed) in the studio.

"Our music lives on, it seems, and you are the one who made it timeless. You were a fantastic inspirer and joy-maker. And the finest sound engineer the world has ever seen. I miss you. And I've saved all your coconuts!"

Bjorn Ulvaeus added: "His significance for ABBA cannot be overestimated. He was a warm, generous person and a good friend. Thanks, Micke, for all the laughs!"

Anni-Frid Lyngstad added her own message in a statement given to Aftonbladet, saying: "You were the security in our little studio bubble with your never-ending creativity, warmth and joy, and no one fit the bill as well as you!

"For us, you are forever part of the ABBA sound and you will never be forgotten!"

Agnetha Faltskog also shared a statement and revealed she was able to spend time with Michael in the weeks before his death. She said: "So glad I got to spend some time with you a few weeks ago ... You were so sick, but your laughter and humor were still there ...

"So many memories are preserved, your encouraging words during the recordings meant so much. We are sad now, a talented and unique person has left us. Sleep well Micke, you are in our hearts forever."

Michael started his career at Metronome Studios in Stockholm in 1967 before starting work with ABBA and joining their Polar Studios in the 1970s.

He became studio manager and worked with the band on albums including 'Waterloo' and 'Super Trouper' as well as rejoining Anni-Frid and Agnetha on their solo material.