Mozart’s horn concertos are a repertoire rite of passage for any player of the instrument. One recording – by Dennis Brain, the Philharmonia and Herbert von Karajan – retains something like legendary status seven decades after its appearance. And there can be few works (pace Grieg) that became so lodged in the consciousness of the wider public than the finale of Concerto No 4 after a comedy duo of the past got their satirical mitts on it.

It’s easy to see and hear the appeal: four works that fit easily on a single album, bursting with Mozartian tunefulness and not delving too deeply into emotional ambiguities (partly due to the chromatic limitations of the valveless natural instrument of the 18th century). Musicologically, though, the horn concertos are a bit of a minefield. No 1 was written last, during Mozart’s final year, and left unfinished, to be completed by his much-maligned amanuensis Süssmayr. No 2 came first, in 1783, then No 4 (1786) and No 3 (1787). In addition, there are two fragmentary attempts at a concerto from 1781, shortly after Mozart arrived in Vienna. Mozart’s son cut up the manuscript of the first of these, to hand out as souvenirs, and it took years for enough of them to be reassembled and the remaining gaps papered over, while the second is a sketch that has only recently been reunited with a long lost 60-bar section of the score.

Enter Stephen Roberts, who has not only fully reconstructed these two movements and brought them together as ‘Concerto No 0’ but also provided a new completion for the First (last) Concerto. In addition, this two-movement work has been expanded into a three-movement one through the adaptation of the slow movement of the Second Violin Concerto.

All of this would be as nought if it weren’t for the magnificent artistry of the soloist and driving force behind the project, the British horn player Alec Frank-Gemmill. Best known to UK audiences as principal horn of the Scottish Chamber Orchestra for a decade, he now holds the equivalent position in the Gothenburg SO, alongside parallel careers as soloist (on both modern and natural horns), chamber player and conductor. His virtuosity is remarkable, not only in terms of surmounting the technical challenges that Mozart threw at his favourite horn player, Joseph Leutgeb, but also for the expressive and dynamic range of his playing. Piquant touches of ornamentation and Frank-Gemmil’s own cadenzas and lead-ins never fail to raise a smile. Name a virtuoso horn player of the recording era and they’re bound to have set down the Mozart concertos. With faultless accompaniment from the Swedish CO under Nicholas McGegan, this exhilarating recording ensures that Alec Frank-Gemmill’s name is now prominent among them.