It's from the first three series of Blake's 7, produced by the BBC... The Liberator was nigh invincible in her exploits against the corrupt Terran Federation, but she was eventually consumed by a strange corrosive substance (fungus?) and destroyed. Her replacement for the final series was the more Star Wars inspired but less impressive or iconic Scorpio.
The Liberator wasn't built by a bug race. It was constructed by a race who slaved themselves to a giant computer known as the System - this race featured only once in the programme's run, which was the first episode of series two, "Redemption".