A self-taught drummer, Diamond played in a variety of local bands including Sound of Time in his native town while working in electrical distribution.

With Adrian Fisher on guitar and Diamond on drums, in the midst of power strikes and a threatened vinyl shortage,[10] they recorded their breakthrough Kimono My House in 1974, scoring a number 2 hit with the single "This Town Ain't Big Enough for Both of Us".

Remembering Diamond's early years with Sparks, producer Muff Winwood said "Dinky was by no means a great drummer but he suited the material perfectly".

Hits such as "This Town Ain't Big Enough for Both of Us", "Amateur Hour" and "Never Turn Your Back On Mother Earth" led to many appearances on the BBC's flagship music show Top of the Pops.

[5] When The Four Squares failed Diamond gradually drifted out of music[5] and after a series of jobs, in 1998 he and his partner of 21 years Jane Gant moved into a small terraced house in Sandhurst in Berkshire where he was troubled by a noisy neighbour and her partner for five years who slept all day and played loud music all night and who argued loudly in the street.

When the police and local housing association did not take action against the neighbour despite numerous complaints, Diamond got drunk and hanged himself from the loft ceiling in his home on 10 September 2004, though news of his death was only made widely known five months later when the verdict of suicide was confirmed at inquest.