European Commission President Jean-Claude Juncker addresses the European Parliament during a debate on The State of the European Union in Strasbourg, France, September 13, 2017. REUTERS/Christian Hartmann

BRUSSELS (Reuters) - An independent Catalonia would have to apply to join the European Union, the president of the executive European Commission said on Thursday, adding that such a policy would apply to any new state.

Catalonia’s parliament has laid the ground for a referendum on independence from Madrid on Oct. 1, although Spain’s Constitutional Court has suspended the vote. Judges are now considering whether the legislation contravenes Spain’s constitution.

“If there were to be a ‘yes’ vote in favor of Catalan independence, then we will respect that opinion. But Catalonia will not be able to be an EU member state on the day after such a vote,” Commission chief Jean-Claude Juncker said on YouTube and broadcast by Euronews.

Echoing a stance made by his predecessor, Jose Manuel Barroso, Juncker said any newly independent state must follow the same EU membership procedures as all aspirants, citing Scotland and, in jest, his home country, Luxembourg.

“If northern Luxembourg were to cede from the south, the same rules would apply,” Juncker said.

The EU’s accession negotiations are an arduous process that involve complying with all EU standards and rules and winning the consent of all EU governments. This means that Spain would be able to block Catalonia’s EU accession if it wished.

Croatia was the last country to join the EU, in 2013 after first applying for membership in 2003.