Catalans to form 400km 'independence' human chain 11 September 2013 Last updated at 15:29 Supporters of Catalonia's independence from Spain are gathering to try to form a 400km (250-mile) human chain across the region in support of their cause. At least 400,000 people are expected to take part in the event, which comes on Catalonia's national day. Regional President Artur Mas has been urging Madrid to allow the region a referendum on independence in 2014. But he has been unable to get the central government's approval for such a vote in the north-western region. Catalonia - one of Spain's most developed regions - already has a wide degree of autonomy, but the economic crisis has fuelled Catalan nationalism. Pro-independence feelings go back centuries, and the Spanish Civil War strengthened animosity between Madrid and Barcelona. Decisive phase The human chain is expected to stretch across Catalonia: from the border with France in the north, down to the border with the neighbouring region of Valencia. Organisers have called local and national media to document the link-up. Today we want to confirm that people still support independence. We want a date for a referendum," Montse Espina, who was planning to join the chain in the regional capital Barcelona, was quoted as saying by Reuters. Speaking to reporters before the action, Mr Mas said the drive for independence was entering into a "decisive phase." Mr Mas - who has held talks with Spanish Prime Minister Mariano Rajoy twice this year on the issue - said he was committed to dialogue with Madrid. "We do not want a traumatic separation from Spain," Mr Mas said. But he conceded that so far the Spanish government had showed no sign of agreeing to an independence vote. If a referendum is blocked in 2014, the Catalan government said it would turn the 2016 regional elections into a vote on independence. A recent poll for Spain's Cadena Ser radio station has found that support in Catalonia for the vote has risen slightly to 81%, the BBC's Tom Burridge in Barcelona reports. He adds that 52% of those questioned said they would vote in favour independence from Spain. However, public opinion in Spain remains strongly opposed to the idea, and according to the Spanish constitution, a referendum in Catalonia would be "unconstitutional."