James Elroy Flecker had already died of tuberculosis, at the age of 30, when his play Hassan had a successful run at Her Majesty's theatre in 1923. Much as the play suggests what the tragic Flecker might have gone on to realise, Frederick Delius's incidental music for Basil Dean's production was similarly hailed as one of his finest achievements. Since performances of the complete score are rare, this Cheltenham festival performance (marking the 150th anniversary of Delius's birth and also acknowledging Flecker's close connection with the town) was both notable and enterprising.

The Story of Hassan of Baghdad and How He Came to Make the Golden Journey to Samarkand, to give the verse drama its full title, is a complex mix of politics, honour, scimitars, blood, love and potions – and incidental music, however evocative, is by its very nature, bitty. As it was presented here as a dramatic narration, with baritone Philip Smith stepping in with aplomb at the last moment for the Egyptian actor Amr Waked, it fell to conductor Neil Thomson and the musicians of the Southbank Sinfonia to deliver the oriental exoticism and harmonic colour of the piece. Thomson faithfully reproduced the soundworld conjured by Delius's instrumentation – the reedy quality of cor anglais and bassoon effectively used as well as harp and xylophone – and also managed to create a sense of the atmospheric moods and whip up the tensions of the more gruesome elements.

It was in the extended closing scene – as Hassan invests his hopes in Samarkand, setting off with the merchants and their oils, spices and embroideries – that the grandeur of Delius and Flecker's concept emerged: the Wellensian Consort singing from the Town Hall's balcony added to the climactic feeling. This certainly amounted to much more than an academic exercise.