We have become so used to thinking of JS Bach’s youngest son Johann Christian as a purveyor of mid-Classical elegance and urbanity that a disc like this one, which seems intent on throwing such ideas aside in favour of drama and terse energy, can come as quite a shock. Gone is the politeness which has always seemed so at one with the 18th-century English milieu into which these pieces were born, and in its place is a useful prompt that JC was aware of the expressive developments forwarded by the North German school represented by his older brother (and teacher) Carl Philipp Emanuel, but also by the Sturm und Drang composers from Austria. JC Bach has always been acknowledged as having affected the young Mozart, but performances such as these hint at a level of influence which goes beyond a demonstration of Classical grace and points to greater emotional possibilities.

Not that the impression made on Mozart by the G minor Symphony has passed unremarked over the years. This is a work as Sturm-y and as Drang-y as anything by Haydn, but it has never sounded more so than here, as the Akademie für Alte Musik Berlin’s strings sob their way through the long central Andante and cut loose in the outer movements with whiplash tremolandi and thunderous dynamic contrasts reinforced by baleful blasts from the horns.

The E flat Symphony recorded here is less well-known but if anything more remarkable, featuring an expressive slow introductory movement, a scrambling Allegro molto and a brief but extraordinary Allegretto that, in this col legno performance at any rate (I’m guessing that it isn’t marked so in the score), will quickly put listeners in mind of Britten’s Simple Symphony. The Berlin AAM’s brusque delivery suits this piece well, but has less of a place in the keyboard concerto which follows it, an inconsequential but attractive piece (ending with a set of variations on a Scottish folk-tune) which surely demands a more relaxed manner.

The programme ends with a well-wrought and finely expressive Flute Concerto by CPE, which for once sounds rather formal and self-satisfied next to such unusually hot-headed outbursts from little brother. Thus, the disc offers not just excellent performances but an ear-opening reversal of received opinion.