"John William Stevens (10 June 1940 in Brentford, Middlesex - 13 September 1994 in Ealing, west London) was an English drummer. He was one of the most significant figures in early free improvisation, and a founding member of the Spontaneous Music Ensemble (SME).

Stevens was born in Brentford, the son of a tap dancer. He used to listen to jazz as a child, but was initially more interested in drawing and painting (media through which he also expressed himself throughout his life). He studied at the Ealing Art College and then started work in a design studio, but left at 19 to join the Royal Air Force. He studied the drums at the Royal Air Force School of Music in Uxbridge, and while there met Trevor Watts and Paul Rutherford, two musicians who became close collaborators.

In the mid-1960s Stevens began to play in London jazz groups alongside musicians like Tubby Hayes and Ronnie Scott, and in 1965 he fronted a septet. Influenced by the free jazz he was hearing coming out of the United States by players like Ornette Coleman and Albert Ayler, his style began to move away from fairly traditional be-bop to something more experimental.

In 1966 SME was formed with Watts and Rutherford and the group moved into the Little Theatre Club at Garrick Yard, St. Martin's Lane, London to develop their new music. In 1967 their first album, Challenge, was released. Stevens then became interested in the music of Anton Webern, and the SME began to play generally very quiet music. Stevens also became interested in non-Western musics.

The SME went on to make a large number of records with an ever changing line-up and an ever changing number of members, but Stevens was always there, at the centre of the group's activity. He also played in a number of other groups, drumming in Watts' group Amalgam and later forming bands like Freebop and Fast Colour, for example, but the SME remained at the centre of his activities.

In the latter part of 1967 Evan Parker joined the SME and worked closely with Stevens in the group, eventually becoming one of the longest standing members. He later summed up Stevens' approach to improvising in two basic maxims: if you can't hear another musician, then you're too loud; and there is no point in group improvisation if what you are playing doesn't relate to what other members of the group are playing.

Stevens also devised a number of basic starting points for improvisation. These were not "compositions" as such, but rather a means of getting improvisational activity started, which could then go off in any direction. One of these was the so-called "Click Piece" which essentially asked for each player to repeatedly play a note as short as possible.

Stevens played alongside a large number of prominent free improvisors in the SME, including Derek Bailey, Peter Kowald, Julie Tippetts and Robert Calvert, but from the mid-1970s, the make-up of the SME began to settle down to a regular group of Stevens, Nigel Coombes playing violin, and Roger Smith playing guitar. During the mid-1970s Stevens played regularly with guitarist and songwriter John Martyn as part of a trio that included bassist Danny Thompson. This line up can be heard on Martyn's 1976 recording Live at Leeds.

From 1983 Stevens was involved with Community Music (CM), an organisation through which he took his form of music making to youth clubs, mental health institutions and other unusual places. Notes taken during these sessions were later turned into a book for the Open University called Search and Reflect (1985). In the late 70s and early 80s John was a regular performer at the Bracknell Jazz Festival.

Aside from SME, Stevens also ran or helped to organise groups that were more jazz or jazz-rock based, such as Splinters, the John Stevens Dance Orchestra, Away, Freebop, Folkus, Fast Colour, PRS, and the John Stevens Quintet and Quartet. He also contributed significantly to Trevor Watts' group Amalgam and Frode Gjerstad's Detail, as well as collaborating with Bobby Bradford on several occasions.

The SME continued to play, the last time being in 1994 with a group including John Butcher. Stevens died later that year."

Roger Smith is a British guitarist known for his work with London Musicians' Collective, his duo with Neil Metcalfe, plus duos with Adam Bohman, Louis Moholo-Moholo, Pascal Marzan, etc.