The virtuosos reveal the recipe to their 20-year chemistry, and details of their latest collaboration.

Their playing is graceful and impressively accurate, but there is also something more. Anthony Marwood and Aleksandar Madzar hold the Wigmore Hall audience spellbound for the entire duration of their concert together. They bring a level of subtlety to Schubert, Schumann and Brahms that is rare, with an empathy that is understated but striking.

“It’s funny,” reflects Marwood later in the carpeted quiet of Wigmore Hall’s subterranean interval rooms. “Sometimes you meet people in life. And somehow you feel that the other person brings out something in yourself that you didn’t know was there. With Sasha I feel that there’s a kind of musical connection of the soul. The kind of conversations we have are delicious and inspiring and interesting, and the playing is a natural extension of that.”

Madzar has had to dash for the Eurostar after the Wigmore Hall concert. We meet later at the other end of that journey, in his Brussels apartment. He expresses a similar sentiment. “If you are going to work with somebody regularly, you need to be on the same wavelength,” he says. “Musicians...