 The UGT grew rapidly after 1917, and by 1920 had 200,000 members.This era came to a sudden end with the advent of the dictatorship of Miguel Primo de Rivera, who gave a legal monopoly on labor organizing to his own government-sponsored union.While the CNT opted for a radical confrontation with the regime and were prohibited on this account, the UGT, although in disagreement with the dictatorship, adopted a collaborative attitude in order to continue to operate legally.