Three early gems by Harrison Birtwistle brought the 2014 Proms Saturday Matinee series to an end. Thanks to some thoughtful curation by Oliver Knussen, the programme featured works which are often overlooked; although the 1995 Last Night of the Proms catapulted Birtwistle into the public eye (thanks to the uproar which greeted Panic), the pieces which most frequently occupy concert halls nowadays date from the mid-1980s onwards. It was refreshing, then, to hear works dating from 1968-71. Already displaying an assured compositional voice, they show evidence of the preoccupations which have been important throughout Birtwistle's career.

Theatre is one such theme, with the visual element of the pieces just as crucial as the aural. Verses for Ensembles is constructed in terms of units, with instrumental sections both visually and aurally separated. The piece is a round dance of a sort, with huge structural blocks juxtaposed against one another; as it progresses, the relationship between the instruments is altered, gradually affirming the horn's role as the catalyst of events. As the blocks gradually evolve, so the arrangement of the players is altered: soloists step out of their sections, taking up a position at the corner of the stage.

Under Knussen's baton, the Birmingham Contemporary Music Group gave a performance which emphasised the direct, hard-edged elements of the music, while at the same time drawing attention to the sensual lyricism (and even humour) which it conceals. Sustained, long-breathed ideas lent the music an enigmatic, alluring quality, casting the quasi-ritualistic events in a mysterious light. The virtuosic confrontations between different instruments acquired a declamatory air in performance, lending the music a sense of urgency.

In the interview preceding Dinah and Nick's Love Song, Birtwistle referred to his compositional miniatures as the "drawings of my music". Often dwarfed by larger works such as Yan Tan Tethera and Secret Theatre, the performance of this rarely-heard work proved that it is no less important a part of Birtwistle's compositional portfolio. With three oboists and a harpist spaced around Cadogan Hall, this particular piece is haunting and enigmatic. Typical serenade gestures were reconfigured, transformed into unsettling, unresolved statements over mesmerising circular figures. While the oboists may not have been entirely in synchronisation, the slight temporal disparities which occurred only added to the hypnotic effect.

Birtwistle wrote this brief piece as a form of preparation for Meridian, the work completing the programme. The complementary other to Verses for Ensembles, Meridian is both a love song and a meditation on the nature of creative activity. Once again, conflict activates the form, with horn and cello as the antagonists directing the action. With passages of calm suddenly surging to powerful outbursts and the dark instrumentation creating a sense of mystery, the piece is simultaneously dramatic and enigmatic.

Contralto Hilary Summers brought a voluptuous sensuality to texts by Thomas Wyatt and Christopher Logue, her luxuriously creamy voice adding to the fantastical aura of the piece. This was furthered by the ethereal interjections of six sopranos from Exaudi, whose onomatopoetic noises and siren-like swoops supplemented the magical mood. Knussen guided the BCMG in a performance which integrated the narrative episodes into a logical progression, elucidating the tight motivic web which underpinned the piece. Although pared-back in many ways, Meridian is at once alluring and elemental, and the ensemble's performance was sensitive while also lending the piece a sense of mystery and awe.

Oliver Knussen's obvious admiration of these pieces shone through in lean yet nuanced performances, while the enjoyment of the BCMG was clear. Although written over 40 years ago, these pieces remain engaging and bold, making the concert an appropriate way to pay tribute to one of today's most vivid musical personalities.