Major works include the oratorio
The Passion (1962), Symphony No.1 (1964), the Violin Concerto (1966),
Songs of Old Age (1968), Symphony No.2 (1969), the oratorio
Continuing Cities (1989), Symphony No.3 (1995),
In My Childhood (1998) and
Cello Requiem (2018) as well as his six operas. Four of the operas were written for children. Two of them,
Let My People Go and
St. Patrick, were commissioned by the Liverpool Education Authority and first performed by the Liverpool Schools Symphony Orchestra. Song cycles include
Spring 1948 (1956),
The Pity of Love (1966),
Songs of Old Age (1968), the orchestral song cycle
In My Childhood (1998),
Another Spring (2008) and
The Coming (2010). His shorter choral works include the cantata
The Death of Orpheus (1953 revised 2009), the motet
Salvator Mundi (1976),
The Starlight Night (1990), the evening canticles written for Bristol Cathedral:
The Bristol Service (1991) and
Celtic Blessings (1996). Music for dance includes two notable collaborations with
Helen Lewis,
There is a Time (1970) and the
London Children's Ballet,
Ballet Shoes (2001). Warren worked closely with several poets, providing instrumental music to complement spoken words, including
Lares (1972) with
Michael Longley and
The Sound of Time (1984) with
Charles Tomlinson. The first of these was with his contemporary
Seamus Heaney,
A Lough Neagh Sequence (1970). Warren wrote: Heaney made a recording of this version of his poetry with Warren's music in 2011. Many of his shorter works are among his most powerful including the solo cantata for flute, piano and mezzo soprano,
Drop, Drop Slow Tears (1960) and the
Song for St. Cecilia’s Day (1967) scored for tenor, flute, viola, guitar and first performed by
Peter Pears,
Richard Adeney,
Cecil Aronowitz and
Julian Bream. His best selling work as a recording is the orchestral suite
Wexford Bells (1970). ==Selected works==