Unió leader Josep Antoni Duran i Lleida leaves party headquarters after the meeting. Massimiliano Minocri

The leadership of Unió Democràtica de Catalunya, one half of Catalonia’s regionally ruling CiU nationalist bloc, has decided to reject an ultimatum given to it on Monday by coalition partner Convergència to support its plan for independence in the region.

After meeting in Barcelona on Wednesday, party leaders decided they were unable to back the plan and were thus withdrawing three officials from premier and Convergència leader Artur Mas’s regional government.

The CiU federation is represented in local governments and other institutions, and that is not changing” Unió secretary general Ramon Espadaler

Unió party secretary general Ramon Espadaler gave a press conference after the meeting to confirm the departure of himself as regional interior chief, vice-premier Joana Ortega, and agriculture chief Josep Maria Pelegrí from the Catalan government.

Espadaler refrained from clarifying whether the decision meant Unió would not be running on a joint ticket with Mas and Convergència at the September 27 regional elections. “We have not had that debate,” he said.

According to Espadaler the decision to leave the government, which was taken following 16 votes in favor, 10 against and two abstentions, did not mean the break-up of the CiU bloc. “The CiU federation is represented in local governments and other institutions, and that is not changing,” he said.

But it now remains to be seen whether Convergència agrees. Unió sources say that the aim of party leader Josep Antoni Duran i Lleida is for it to be Mas’s decision whether to formally break up the CiU alliance.

The decision to split with the government has been difficult for many reasons, not all of them political. Unió is one of Spain’s most indebted parties and the drop in income that a break with Convergència would bring complicates any move.