Judge Baltasar Garzón arrested eight members of Udalbiltza and ordered the closure of his headquarters. In the summary, 22 people were processed under the doctrine "everything is ETA", nineteen of them elected municipal officials and three workers from Udalbiltza. In 2011 they were acquitted by the National Court of Spain.

Udalbiltza was established on 18 September 1999, when ETA was in full swing and most Basque nationalist political and social forces signed the Lizarra-Garazi Agreement. It brought together 2,000 voters from the seven Basque territories. The objective was the coordinated use of the competencies of municipalities or councils in the path of national construction.

"To overcome the administrative fragmentation of the Basque Country, which contributes to the full development of the Basque Country and the XXI. Because to face the challenges of the century, territorial articulation is necessary", he said.

The new organization soon suffered the Abertzale division and the breakdown of the ETA truce. When Udalbiltza was split into two, the HB was under judicial aggression from the Spanish state since 2003.

In 2013, Udalbiltza was reorganized, in a new environment, but he did not find the same site.