Indelible Murtceps was the alter-ego of 1970s Australian progressive rock band Spectrum. The name 'murtceps' is 'spectrum' spelled backwards.

Influenced by overseas groups like Traffic, the Melbourne-based group developed an extensive repertiore of original experimental progressive rock music, intended for performance in a serious concert setting, using a large PA system and light show, as well as on occasion being augmented by Melbourne performance troupe 'The Tribe'. They commonly performed at larger concert halls, so-called 'head' venues like the T.F. Much Ballroom and at rock festivals

But during the early 1970s the Australian rock scene began to change, and the circuit of festivals, large concert and 'head' venues began to dwindle as the scene shifted towards a simpler, heavier and more accessible style, which has become known as "pub rock". Realising that their lengthy and complex material was precluding them from getting bookings on the lucrative local dance and pub circuit, Spectrum created a set of simpler, dancier music, using a reduced stage setup. They re-christened the band as "Indelible Murtceps" for the purpose, allowing Spectrum to continue on its progressive course while enabling them to supplement their income with the Murtceps gigs.

In late 1972 they recorded the album Warts Up Your Nose, produced by Peter Dawkins. It featured a selection of the songs they performed as Murtceps, most of which featured satirical, scatalogical and sexual themes; the centrepiece was Rudd's epic 13-minute ode to mariujana, "Some Good Advice". The album was packaged in a brown cardboard cover, intended to evoke the "plain brown wrapper" tradiitionally associated with pornographic publications. They released one single, "Esmeralda" which (like the song "Rene" by The Small Faces) was a lighthearted ode to a prostitute. They released two singles as Murtceps -- "Esmeralda" / "We Are Indelible" and "Indelible Shuffle" / "Ray's Boogie".

The Warts album was the last to feature original keyboard player Lee Neale . He suffered a nervous breakdown shortly after the album was completed and he left the band in September 1972, to be replaced by Canberra-born John Mills. Neale abandoned the music scene for good and dropped completely out of sight; to this day his former bandmates do not know of his whereabouts or what became of him after leaving Spectrum.