In the mid-1970s, Mandelson was a student at Bolton Institute of Technology (now Bolton University), where he met Howard Devoto, future Buzzcocks and Magazine frontman. When punk emerged, he formed a band called Amazorblades, being the group's guitarist.
In 1982 as Hijaz Mustapha, he started playing with Lu Edmonds a.k.a. Uncle Patrel Mustapha Bin Mustapha, which led to the formation of 3 Mustaphas 3, a band that was active throughout the 1980s and into the 1990s. In 1982, he also worked with dub and roots reggaeBlack Uhuru sound engineer, Godwin Logie, and with ex Public Image Ltd bassist, Jah Wobble.
In 2009, together with Justin Adams and, again, Lu Edmonds, Mandelson formed the band Les Triaboliques[7] and released the debut album Rivermudtwilight.[8]