Now that the Nazi era and the Holocaust have passed into history, it is difficult to imagine a time when choices could still be made – when musicians, with their eyes on the approaching Brahms centenary in 1933, could keep their heads down and mutter, in effect: ‘I’m just a Musikant, I don't get involved in politics’. For Busch, Brahms loomed large without blotting out what was happening all around. Yet even he, who had so often warned about the onset of Nazism in Germany, could not know how close he was to the precipice over which his country, his profession and his own life would soon tumble. At the outset of the 1932–33 season, he stood at the pinnacle of his career. Virtually every work he composed was assured of performances and he featured in the catalogues of three leading publishers. Among German executant musicians, his distinction was rivalled only by Furtwängler, Walter and Backhaus. No Beethoven, Brahms or Reger festival was complete without him. ‘He was unquestionably the greatest German violinist’, Szymon Goldberg said, and Berthold Goldschmidt attested that: ‘Busch was always considered in Germany as a typical German musician and fiddler, the one and only interpreter of Beethoven and Brahms’. As the inheritor of Joachim's mantle, he had a bulging concert diary, in which the name Brahms appeared on virtually every page: apart from innumerable bookings at home and abroad for the Concerto – his edition, with cadenza, was being published by Breitkopf – he planned an exhaustive review of the chamber music.

For the Quartet and Serkin the season started in London, ushered in by Busch's first Promenade Concert engagements: the Brahms and Beethoven Concertos in Queen's Hall on 14 and 16 September respectively, with Sir Henry Wood and the BBC Symphony Orchestra. He confessed to friends that he was put off initially by the Promenaders milling about in the body of the hall, where the seats were removed for the Proms; and the composer Harold Truscott noted that he looked nervous in the opening tutti of the Brahms, transferring his violin from one hand to the other, placing it under one arm and finally playing along with the first violins – an old campaigner's stratagem for steadying nerves and checking tuning.