The Cheltenham Improvisers Orchestra (C.I.O.) are a 15-20 piece group using a broad range of acoustic and electronic instrumentation, playing either totally free improvisation or involving some kind of conduction. The C.I.O. has a mixture of non-traditional musicians alongside more seasoned improvisers, such as Chris Cundy, Mike Adcock and Pete Robson. Recent performances have included some very special guests, Ernst Reijseger, Mick Beck, Hannah Marshal, John Bisset, Tim Hill and Diatribes.