Catalonia's deeply divided separatist movement will put its mobilisation skills to the test Saturday as the northeastern region celebrates its national day ahead of fresh talks with Spain's government.

The annual "Diada" on September 11 marks the fall of Barcelona to Spain in 1714 and normally draws vast crowds of more than one million people.

This year's celebrations will be the first since Spain pardoned nine separatist leaders who were serving long jail terms over their involvement in a failed 2017 independence bid.

Under the slogan, "We will fight for independence and win", the Catalan National Assembly (ANC), the region's biggest grassroots separatist movement, is planning to march through Barcelona in an annual rally that at its peak brought 1.5 million people onto the streets.

But many things have changed since the frenetic autumn of 2017 when the Catalan regional government staged a referendum banned by Madrid and then issued a short-lived declaration of independence, triggering Spain's worst political crisis in decades.

Those behind the move were arrested, tried and sentenced to long jail terms by Spain's top court, while others fled abroad to avoid prosecution, leaving the movement deeply disappointed and sharply at odds over how to proceed.

"Since 2017, morale has hit a real low, but the fact that there were political prisoners (in jail) gave them something to keep fighting for," Berta Barbet, a political scientist from Barcelona's Autonomous University, told AFP.

"Now that is gone (following the prisoners' pardon), the real lack of driving force is clear for all to see."

Also weighing on the mood is friction within Catalonia's new separatist-led government, which groups the moderate leftist ERC that favours a negotiated strategy to achieve independence, and its more radical junior partner, JxC, which wants to keep up a confrontational approach.

Such pressures have depleted the numbers at recent Diadas, with only 600,000 hitting the streets in 2019, the lowest number in many years.

In 2020, coronavirus-related health restrictions reduced the celebrations to a handful of separate events which drew fewer than 60,000 people.

The separatist camp also suffered a setback this week before the European Court of Human Rights, which dismissed complaints from two people who say they were the victims of police violence during the 2017 referendum.

This year's celebrations will be the first since Spain pardoned nine separatist leaders
This year's celebrations will be the first since Spain pardoned nine separatist leaders AFP / Josep LAGO

Despite everything, independence is deeply rooted within this wealthy region of 7.8 million residents.

"Even though it is going through a difficult moment politically, the independence movement is still very strong on the street," said Barbet.

And that was on show in regional elections in February when the separatists managed to garner more than 50 percent of the votes.

Following weeks of tense negotiations, Pere Aragones, a moderate ERC separatist, was finally installed as regional leader in May.

A small player within Spain's parliament, ERC has offered crucial support to the minority government of Prime Minister Pedro Sanchez, and when it took over as senior partner in the Catalan administration, it had an immediate effect.

Within weeks, the Spanish government had pardoned the separatist leaders and agreed to resume top-level talks on resolving the Catalan crisis.

Sanchez and Aragones are scheduled to meet next week, although there is still no fixed date and it remains unclear whether the Spanish premier will attend the talks in person.

What is clear is that both sides will come to the table with radically different roadmaps.

The Spanish government is against the key demands of the separatists -- namely, an amnesty for all those involved in the failed independence bid, which would exonerate those who fled abroad, and a referendum on self-determination, this time with Madrid's approval.

"There is little or no room for agreement", said Lluis Orriols, a political scientist at Madrid's Carlos III University.

"The central government can offer greater regional powers, it can seek to hold a referendum with different parameters, but only as long as it doesn't infringe on Spain's constitution," he said.

Still, there is hope that the negotiations will ease tensions at a key moment of economic recovery from the Covid-19 pandemic.