UG was founded as the successor of the PSG-EG in 1991.
The party presented a coalition with United Left (EU) for the Galician elections of 1993 and for the Spanish elections of the same year, failing to gain any seats in both.
In fact, UG, lost the 2 MPs that the PSG-EG had in the Parliament of Galicia between 1989 and 1993.
After the election failure, UG joined the BNG in 1994.
[1] On the 20 of September 2003 UG decided to disappear as a political party and became an "opinion current" inside the BNG.