Simon H. Fell (13 January 1959 – 28 June 2020) was an English jazz bassist and composer; he is primarily known for his work as a free improviser and the composer of ambitiously complex post-serialist works.

Fell began playing double bass in 1973. From 1978 to 1981 he read English Literature at Fitzwilliam College, Cambridge, an interest that led to ties to many of the poets associated with the Cambridge scene (a later work, Music for 10(0), involves settings of texts by the poet/music journalist/provocateur Ben Watson).

Fell's most notable early group was a group with drummer Paul Hession and saxophonist Alan Wilkinson, a free-jazz trio that was exceedingly fast and furious even by the standards of that genre. Their work was primarily released as cassettes and CDs on Fell's label Bruce's Fingers, including Bogey's and the group's only studio album, foom! foom! Their most sonically extreme statement, however, was the grainily recorded The Horrors of Darmstadt (Shock). (Its title is a sarcastic quotation from a BBC announcer, concerning the avant-garde Darmstadt School of composers.) During this period Fell was significantly connected with The Termite Club in Leeds. His previously mentioned Music for 10(0) was written to celebrate ten years of the existence of the club.

Other groups in which Fell was a member included the free jazz trio Badland (led by saxophonist Simon Rose; initially the drummer was Mark Sanders, with Steve Noble subsequently taking over the role), the improvising string and percussion ensemble ZFP (with Carlos Zingaro, Marcio Mattos and Mark Sanders), and SFQ, a quartet/quintet with changing membership, though clarinettist Alex Ward has been a constant. (Fell's 2001 version of his 70-minute SFQ composition Thirteen Rectangles was broadcast twice by the BBC, and subsequently nominated for the 'new work' award in the 2002 BBC Jazz Awards.) In sharp contrast to the uproar of Hession/Wilkinson/Fell, the trio IST (with Rhodri Davies and Mark Wastell) was one of the seminal groups in the development of the ultra-quiet aesthetic now generally called "EAI" or "electroacoustic improvisation". Fell also performed in many other ensembles, including the London Improvisers Orchestra and Derek Bailey's Company Week.

Fell's major sequence of compositions is titled Compilation (in total, four projects were issued under this heading). Despite the governing title, these are not collections of previous material but new, large-scale works. The musical language makes overt use of serialist procedures (such as tone rows, retrograde structures, &c), as well as many other techniques: extensive studio layering, overdubbing and reordering of material (so that seemingly "live" performances may be the result of carefully edited-together improvisations and/or notated material), and use of aleatoric techniques to "degrade" or distort precomposed structures into new shapes. Free improvisation, rock and jazz all form key parts of the musical language; one section of Compilation IV even includes a simultaneous homage to Karlheinz Stockhausen and Henry Mancini. The cast of musicians drawn on for these pieces usually included a mix of classically trained players, jazzers and free improvising musicians, as well as wild cards like the noise guitarist, Stefan Jaworzyn. While virtuoso players such as Evan Parker and John Butcher were essential to the projects, Fell often deliberately made use of amateur or student musicians, too, not as a makeshift but as an intentionally democratising and less predictable element.

Fell died on 28 June 2020.

Other large-scale composition projects included:

his compositions for The London Improvisers' Orchestra (Papers, Happy Families, Köln Klang, Ellington 100 (Strayhorn 85), Morton's Mobile, Too Busy and Three Mondrians) (1998-2004) Kaleidozyklen, a 60-minute piece for improvising double bassist and orchestra (2000) Thirteen New Inventions, a major solo piano piece commissioned by Philip Thomas (2005) the concert-length BBC Radio 3 commission, Positions & Descriptions (for 18 musicians and prerecorded materials), premiered at the Huddersfield Contemporary Music Festival (2007) a one-hour suite for sextet, The Ragging Of Time, commissioned by the Marsden Jazz Festival (2014)