The Electric Light Bulb were a pop/prog-rock band in the late 70's and early 80's. Their stadium performances were renowned for their stunning light shows.
The term "progressive rock" was coined from an NME article when they described the experience of listening to an early Marillion album as: "like swallowing a small rock and feeling it progress through your intestines until it bursts out of your bum bringing with it all the putrid garbage that it gathered along the way"