Darius has been music director of the Sheffield Philharmonic Chorus since 1997. In addition to preparing them for visiting orchestras and conductors - including Mark Elder, Gianandrea Noseda, Nicholas Kraemer, and Paul Daniel - he has conducted the choir in performances with the Halle, Royal Liverpool Philharmonic and Northern Sinfonia, and directed from the harpsichord with the Manchester Camerata. Since he took over as music director, the choir has performed from memory for the first time, and has appeared at the Proms and on recordings for Chandos with the BBC Philharmonic including Elgar's Crown of India with the BBCPO and Sir Andrew Davis for Chandos Records. Before taking up his post at Sheffield he was chorusmaster of Leeds Philharmonic Chorus.

He has worked regularly as guest chorusmaster or conductor with many other choirs including the Northern Sinfonia Chorus, Leeds Philharmonic Chorus, Huddersfield Choral Society, CBSO chorus and Netherlands Radio Choir, with whom he has specialised in contemporary music, having prepared them for works by Berio, Boulez, Ligeti, and the premiere of Stockhausen's Engel-Prozessionen. Recent projects include working with the Lucerne Festival Academy in preparation for a performance of Berio’s Coro conducted by Simon Rattle, guest chorusmaster for the Northern Sinfonia for Paul McCreesh, and conducting the BBC Philharmonic in a CD of music for the BBC Young Choristers of the Year. He recently directed the choir with the Black Dyke Band in premiere recordings of the brass band arrangement of Rutter’s Gloria, and Paul Mealor’s new work Paradise.