Bach's Brandenburg concerto No. 3 (BWV 1048) doesn't have a slow movement. In the place where you would normally expect to find one, what's written out is just two chords. And in most modern performances, those chords get a perfunctory embellishment, a quick bit of a cadenza, and on we go. That's the shape in which the piece now sits in the classical canon, so nobody expects more than that. The players, for example, can't wait to hunker down to the third movement, a joyous G major allegro, 48 bars plus repeats of 12/8, rosin flying, semiquavers in perpetual motion, see you at the end.
On the internet I've across people who do like to give their opinions on this question. Some are merely nerdy. Others are downright weird. Reading their discursions, the whole thing can start to resemble the question of why Swiss cheese has holes in it.
But for the Aurora Orchestra's concert on Saturday in the Corn Exchange in Cambridge, a repeat of a programme given a week before in LSO St Luke's in London, conductor Nicholas Collon not only conceived of a superb idea, he also put it into practice. He chose to insert Arvo Pärt's "If Bach had been a Beekeeper" in the place of the missing slow movement. And in doing so he would appear to be onto something good. To my knowledge, it's the first time it's been done, but the idea is bound to be tried again,so I hope that Collon gets all the credit due to him for having dreamt it up.