In later years he worked principally as a songwriter, and is perhaps best known for co-writing the song "Torn" (made famous by Natalie Imbruglia) and for writing two UK number one hits for Pixie Lott.

He began working as a recording engineer in 1978 at RAK Studios in London for producers Mickie Most, Steve Lillywhite and Alex Sadkin.

[1][3] The following year, he produced the non-album Cure single "The Love Cats" and contributed a distinctive double bass performance on the song.

[2][6] Also in 1988, he joined the pop band Johnny Hates Jazz, which included his friend Mike Nocito, on lead vocals and various instruments,[7] and appeared on their 1991 album Tall Stories.

In 1991, Thornalley co-wrote, with Scott Cutler and Anne Preven, the song "Torn" which later appeared on the 1995 debut album by American alternative rock band Ednaswap.

[9][10][11] Thornalley has also written hit songs for BBMak,[12] and in the early 2010s he wrote two UK number one singles – "Mama Do" and "Boys and Girls" – for Pixie Lott.