The worlds of Scottish theatre, music and publishing are mourning the loss of a kenspeckle figure in the cultural life of Scotland, Derek Watson, who has died after a short illness at the age of 69.

A composer, pianist of renown, an actor and musical director as well as a bookseller who owned his own bookshop in his home village of West Linton in the Scottish Borders, Watson was an acknowledged expert on the composer Richard Wagner.

His biography of Wagner was well received when it was published in 1979, and he added to it with volumes on Bruckner and Liszt in the Master Musicians Series.

As an actor, using the stage name Derwent Watson, he appeared in nearly 60 productions with the Glasgow Citizens Theatre Company and also worked in London’s West End with several of the leading theatre companies, and had numerous appearances on BBC TV and radio.

He regularly gave lectures on opera and contributed articles to the New Grove, the Oxford Companion to Music, and several other musical and academic periodicals.

It will be for his work at the Citizens and elsewhere in Scottish theatre for which he will be best remembered, with his kindly enthusiasm as a musical director earning him the nickname Uncle Derek.

His love for books was apparent in his shop Linton Books, and he was also well known in publishing .

His great friend, the Braveheart actress Gerda Stevenson, who is also from West Linton, led the tributes to Watson on social media.

She wrote: “He was a great character, a marvellous human being, so gifted. A fine musician, an authority on Wagner – the Wagner Society of Scotland was founded in 1984 under the chairmanship of Derek – Liszt and Bruckner, and not only an actor for many years, including at the Citizens Theatre in Glasgow, but also a musical director.

“In the latter role he was lovingly known within the Scottish theatre profession as ‘Uncle Derek’. He had such an appetite for life, and for justice. And, oh, he was such fun to be with. What a massive gap in our community’s life.”

Actor Ron Donachie replied to Stevenson’s news saying: “Very sorry to hear that, Gerda. He was all the things you say, a lovely man, a splendid colleague and a great pleasure to be with.”

Taggart actor Alex Norton described Watson’s death as “such sad news,” adding “I worked with uncle Derek at the Citz Pantos in the 70s. A truly wonderful and unforgettable person.”

His fellow Taggart star Blythe Duff wrote: “Uncle Derek. What a charm he brought to the Citz. Sad news.”

Still Game star Gavin Mitchell wrote: “Awful news. Uncle Derek looked after me in my first ever production and many more.”

A Yes Linton event Watson was due to compere at last night has been postponed and will be held at a future date in his honour.