Thornalley has worked primarily as songwriter and record producer for other artists. In 1991, he co-wrote "Torn" (with Scott Cutler and Anne Preven), which later appeared on Ednaswap's 1995 debut album. Subsequently, he was asked to produce some songs for Natalie Imbruglia, and "Torn" was re-recorded alongside four other songs Thornalley wrote on Imbruglia's 1997 seven million selling debut album "Left of the Middle", and became a worldwide hit single. In 2012, the single was covered by One Direction on their live concert DVD "Up All Night: The Live Tour".