Spanish and Catalan flags inside the regional parliament on Wednesday. Albert Garcia / EL PAÍS

Spanish Prime Minister Mariano Rajoy is scheduled to meet on Thursday with opposition leaders Pedro Sánchez of the Socialist Party (PSOE) and Albert Rivera of Ciudadanos to craft a joint response to the secessionist challenge in Catalonia, where the regional parliament on Wednesday passed a law to hold an independence referendum on October 1.

The Socialists reiterated their support for the Spanish executive “in defending the rule of law,” while Ciudadanos said that Rajoy can count on their “unwavering” support. All three parties contend that the referendum is illegal on the basis that it violates existing Spanish and international legislation on many fronts.

We are trying to prevent a dangerous social and political conflict

Ferran Pedret, Catalan Socialists

But the left-leaning Podemos is opting out of this alliance, and rejects the governing Popular Party (PP)’s “use of judges and courts to avoid political channels,” a reference to the fact that the PP will appeal the Catalan law before Spain’s Constitutional Court.

Despite the show of unity in Madrid, the Catalan branch of the Socialist Party said on Thursday that it will not support an initiative by Inés Arrimadas, head of Ciudadanos in Catalonia, to mount a no-confidence motion against the Catalan government. “We don’t think that’s a good solution,” said a spokesperson.

Instead, the Catalan Socialists (PSC) want to try other avenues. “We are trying to prevent a social and political conflict that could be very dangerous,” said Ferran Pedret, a regional deputy for the PSC, in a television interview. “There is still time for dialogue.”

Following a marathon session that began at 10am on Wednesday and ended at 2am with the passage of the controversial Law on the Self-Determination Referendum, deputies convened again on Thursday at 10am to debate another bill called the Juridical Transience Law, which secessionists say would make Catalonia a legal state if “Yes” wins at the October 1 referendum.

With a little over three weeks to go, the Catalan government is going into high gear: on Thursday it unveiled a new website in four languages (Catalan, Aranese, Spanish and English) containing practical information about the referendum, including a call for international monitoring.

“The Government of Catalonia welcomes both non-governmental organizations and individuals who wish to partake in the observation of the referendum on site in order to witness the proceedings throughout the day, thus guaranteeing the democratic quality of the Referendum,” reads the website.

Regional premier Carles Puigdemont has also sent letters to local authorities asking them whether they are willing to loan public buildings to set up ballot boxes.