Colin Mawby KSG (9 May 1936 – 24 November 2019) was a leading English composer, organist and choral conductor renowned for his lifelong contribution to Catholic liturgical music.

Born in Portsmouth, he was educated at Westminster Cathedral Choir School, becoming assistant organist to George Malcolm at age 12. He later studied at the Royal College of Music with Gordon Jacob and John Churchill, working with conductors Adrian Boult and Malcolm Sargent.

In 1961, aged only 25, he was appointed Master of Music at Westminster Cathedral, a post he held for 15 years. During this time he conducted premieres with Pro Cantione Antiqua, collaborated with major orchestras and choirs, and performed for royalty, presidents and popes, including at St Peter’s Basilica for Paul VI and John Paul II.

In 1981 he moved to Dublin as choral director of Radio Telefís Éireann (RTÉ), where he founded the RTÉ Philharmonic Choir, RTÉ Chamber Choir and the children’s choir RTÉ Cór na nÓg. He retired to England in 2001 but continued composing until late in life.

Mawby’s vast output includes many Masses (notably the Missa solemnis Bonifatius-Messe, 2012), motets, hymns and antiphons widely used in English-speaking Catholic churches. His Ave verum corpus and Psalm 23 gained international fame through Charlotte Church’s recordings. He also wrote two children’s operas, a Requiem of Hope (1995–2002) and a prize-winning Prayer of Forgiveness (2002).

In 2006 Pope Benedict XVI created him Knight of St Gregory the Great for his services to church music. He died in 2019, aged 83, leaving a rich legacy of accessible yet sophisticated sacred music still sung worldwide.