Thomas Søndergård, Principal Conductor of the BBC National Orchestra of Wales delivered a fascinating and contrasting programme for the orchestra’s fourth Proms outing this year. Definitely a concert of two halves, they began with two English works separated by nearly 60 years, and followed with two works strongly connected by form from the earlier Austro-Germanic tradition.

Walton’s Partita provided a lively opener, and Søndergård and the NOW relished the metallic brightness of the opening Toccata. The successive solo passages in the harmonically troubled central Siciliana did not always dovetail as neatly as they might have, and a little momentum was lost here, but the comic raucousness of the final "Giga burlesca" made up for this in energy.

Pianist-composer Huw Watkins has already had two of his concerti premiered at The Proms, his Double Concerto for viola and cello (2005), followed by his Violin Concerto written for Alina Ibragimova (2010). His latest Proms commission is a family affair, a Cello Concerto written for, and performed here by his older brother, Paul Watkins. Although conventionally in three movements, Watkins’ Concerto reverses the usual tempo structure, with two slow outer movements surrounding a central Allegro. However, even the Allegro's faster tempo is relatively short lived, with the music settling into relative stasis soon after the skittering opening.

Later in the movement, whilst the cello has some challenging rapid rhythmic movement, it is set over slow-moving orchestral writing, so the overall sense is not one of pace. The opening movement focuses on the cello’s lyrical quality, with long, meandering lines supported by subdued writing for woodwind and muted strings, centred around falling and rising fifths. This is particularly effective when Watkins pares the forces down to front desk strings, and there is a sense of sadness and unease in this meditative movement. The final movement in many ways mirrors the first, with a return to long, slow lyrical lines for the cello. The pace quickens briefly, with a short passage of greater rhythmic complexity, but after a restrained build to the climax, the music falls away back to the solo lyrical line over rich string chords, before dying away to nothing. There were moments of real beauty here, and this is definitely a work that would merit a second hearing in a more favourable acoustic – despite Watkins’ careful light orchestration, there were still moments when the cello struggled to be heard. As a concerto, it highlights one facet of the solo instrument, with limited opportunity for livelier virtuosic display, but it certainly exploited Paul Watkins’ consistently warm tone well, and this was an engaging performance of a promising addition to the concerto repertoire.

Pairing Webern’s Passacaglia with Brahms’ monumental Symphony no. 4 is a clever move. Webern’s concern with making links with the past, at the same time as grappling with the future, to a certain extent mirrors Brahms’ own creative struggles, although Webern clearly broke free more radically moving into atonality and serialism. Both works also share their updated use of the old passacaglia form, a structure of variations based not on a melodic theme, but a somewhat chromatic bass line, which could be seen as a foretaste of serialism to come.

Webern’s Passacaglia opens with a very quiet, bare pizzicato statement of the theme, and Søndergård understandably could not wait for too long for the audience hubbub to die down before commencing. Consequently, it was only when the melancholy flute melody was added for the first variation that they caught the audience’s attention. Søndergård paced the calculated arcs of the three ‘paragraphs’ of variations, and managed the slightly seasick swells and surges as the intensity built. With well-controlled solos from the trumpet and clarinet in particular, this was a taught and arresting performance of this highly individual masterpiece.

Søndergård’s Brahms was an unexpectedly controlled affair. He chose flowing yet slightly swift tempi, and gave little space for indulgence, notably in the first movement’s lyrical cello second subject, which could have done with a little room for manoeuvre. There was some fine playing from the BBCNOW, with sweet string tone and incisive woodwind playing throughout. The horn section was not always in perfect blend, and the beautiful brass chorale where horns join with trombones in the finale suffered from the great distance between the two sections on either side of the stage. But otherwise, this was a highly proficient performance, and, as in the Webern, Søndergård managed the trajectory of the final passacaglia with confident command. Unlike that second subject in the first movement, the flute solo in the twelfth variation was given just the right amount of flexibility combined with effortless control, and the relentless build after this temporary respite towards the compressed coda had an inevitable momentum, leading to a suitably emphatic and energetic conclusion.