Beethoven’s Emperor Concerto is one of those imperious E flat major works. It epitomises the key’s sturdy grandeur. I have had a CD of this and the fourth piano Concerto in my car to listen to on commutes.

Movement one was rocksteady E flat major when I listened to it on one journey. I anticipated that the slow movement, written in B major (a lush key) would sound up a semitone in C major (a strong key still in my changing tonal universe), and it did. Not unpleasant, but having more of a sweet feeling, like Shostakovich’s C major second movement in his second Concerto, than deep Beethoven. What would happen as the horn’s long B (now a C, of course) slipped down in preparation for the finale, an energetic E flat major Rondo?

What happened was unprecedented – the third movement headed off in no recognisable key. Not E flat, not E (the semitone up) – nothing! I know this piece well. I have bashed my way through the piano part many times, but I could not pin this down. The development section, I knew takes  thematic material based on the main theme up and down the piano through three keys: C, A flat and E Majors, so I waited to see what would happen. The first chord of the C major section was instantly ‘in key’. The shift to A flat – ditto, and likewise the E major section. Beethoven then modulates through E minor, A minor, D major, and G minor broken chords back towards E flat major, spending a lot of time on a B flat dominant seventh chord that presages the return of E flat major and the main theme. By the time we got there we were back in “no” major, and so we stayed till the end of the piece. “Eeeuuuuchhhh!”, as they say in the comics. Tasteless pap. Not Beethoven.