"The government of Britain and Scotland agreed on a referendum," the president of the regional Catalan government, Carles Puigdemont, and his vice president, Oriol Junqueras, wrote in a letter published in daily newspaper El Pais yesterday.
"And everything indicates that Scotland and Britain will once again agree on the celebration of a new referendum on independence."
Scotland's First Minister Nicola Sturgeon today demanded a new independence referendum by early 2019, once the terms of Britain's exit from the European Union are clearer.
In Scotland's 2014 plebiscite, 55 per cent backed staying in the UK.
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"The scenario of an agreed referendum is what we desire in Catalonia," the Catalan leaders wrote in their letter.
"We would like to recall that we have proposed it on various occasions. Today, despite the bad omens and the outright rejection of the Spanish government, we once again insist on it."
The government of Catalonia, a wealthy region in northeastern Spain that has its own distinct language and is home to 7.5 million people, has since 2010 sought to hold an independence referendum.
The Catalan government has vowed to hold an independence referendum by September -- with or without the approval of the central government.
"We will do the unspeakable so that the citizens of Catalonia can vote in 2017 in an auto determination referendum," Puigdemont and Junqueras wrote.
Demands for autonomy have been fuelled by Spain's economic downturn, leading many to resent sending tax money to Madrid to prop up poorer regions.
Opinion polls show Catalans are evenly divided on independence, although the vast majority back a referendum.