BARCELONA/MADRID (Reuters) - A general strike called by pro-independence campaigners in Catalonia closed shops and severed transport links on Wednesday, as the region s deposed leader lost political momentum after failing to seal an electoral pact with another party. Protesters closed roads, causing huge tailbacks into Barcelona, while some public transport ran minimum services and some smaller stores remained shuttered. Reuters saw hundreds of strikers gathered in Barcelona s main Sant Jaume square to protest the imprisonment of politicians, chanting the name of ex-leader Carles Puigdemont and referring to him as  our president . But he faces an uphill task to maintain influence after he missed a deadline of midnight on Tuesday to agree a pro-secessionist pact for a regional election with his former vice president Oriol Junqueras. The central government in Madrid called the election for Dec. 21 after last month assuming control of Catalonia following its parliament s unilateral independence declaration. Spain s Constitutional Court on Wednesday officially annulled the declaration, which it had suspended, a widely expected ruling. Catalonia s secessionist push has plunged Spain into its worst political crisis in four decades, leading to a business exodus and reopened old wounds from the civil war in the 1930s. Junqueras is in custody on charges of sedition, rebellion and misuse of public funds. But polls show his leftist ERC party will win three times as many seats next month in the regional assembly than the centre-right PDeCAT of Puigdemont, who is in self-imposed exile in Belgium and facing the same charges. If that forecast proves correct  it represents a very uncomfortable position for Puigdemont,  said Jose Miguel de Elias, of political consultancy Sigma Dos.  If (the secessionists) get enough seats to form a government, he would be vice president, which ... would not suit him.  In Catalonia there was a mixed reaction to the pro-independence strike, called by two civic groups, whose heads were imprisoned last month on sedition charges, and a labor union. People stood across dozens of major highways waving placards and chanting  freedom for political prisoners , TV and video images showed, while minor scuffles were reported on social media as police attempted to move protesters. While many smaller stores left their shutters down due the strike, most larger shops and businesses appeared to be open as normal.  Why should I strike, nobody is going to raise my salary... The politicians should work more and stop their silliness,  Jose Luis, a Barcelona construction worker, told Reuters TV on his way to work. Protester Josep Cardona, a 55-year-old office worker, had not joined a previous strike, but this time  with putting people in prison, it has all gone too far,  he said. Strike supporter Nuria Catalana, a 64-year-old nurse, said she had favored a pro-secessionist electoral pact, but understood the difficulties involved.  We ll have to see if they really pay attention to whoever wins the election. We have to continue the struggle,  she said. Puigdemont had ambitions to garner support for his independence campaign in the heartland of the European Union.  But that hope has fallen flat, and in an interview published on Wednesday he renewed criticism of the bloc s executive.  (EU Commission President Jean-Claude) Juncker welcomes mayors, governors ... but he doesn t want to meet me,  Puigdemont told Belgian Daily De Standaard.   I ve always been a convinced European ... But the people who are running the EU now are wrecking Europe.  Prime Minister Mariano Rajoy, who has been unwavering in his opposition to any form of independence for Catalonia, said he hoped next month s election would usher in  a period of calm  and business as usual for the region.  I m hoping for massive participation ... and, after that, we ll return to normality,  he said in the Madrid parliament building on Wednesday. An opinion poll released on Sunday by Barcelona-based newspaper La Vanguardia showed Junqueras  ERC could garner 45 or 46 seats in the regional assembly and Puigdemont s PdeCat just 14 or 15. That would leave them needing to form a parliamentary alliance with anti-capitalist CUP to reach the 68-seat threshold for a majority. ERC and PDeCAT could still reach an agreement after the vote, but by standing together they could have held more seats, polls and projections from the 2015 election results showed. 