Progressive parties around Europe are pinning their hopes on Spain to confront the populist right in the EU parliament after the Socialist Party (PSOE) prevailed in a “Super Sunday” of polls dominated by domestic division over Catalonia.

Although insurgent challenges loom large in Brussels and Barcelona – not least from exiled and jailed Catalan leaders who were elected MEPs – Spain’s Socialist prime minister Pedro Sanchez translated his recent general election success into a hat-trick of overwhelming victories at the European, regional and local levels.

In Europe, Mr Sanchez – often seen as Emmanuel Macron’s Mediterranean, market-sceptic counterpart – is set to lead the talks over key institutional roles on behalf of the social-democratic parties after PSOE won 32.8 per cent of the vote, the largest share of any of its continental partners, apart from the Portuguese socialists.

“We are going to be the biggest social democrat delegation, and that’s a source of pride for us. It’s an opportunity, but also an enormous responsibility,” a beaming Mr Sanchez said early on Monday before heading to meet the French president in Paris.

His was also the best-performing governing party in Sunday’s elections, beating Matteo Salvini’s anti-globalisation Liga Nord (Northern League) from Italy – casting Mr Sanchez, who has so far managed to contain the threat of Vox in Spain, as a protagonist in the fightback against the far right influx within the EU.

EU elections 2019 Europewide results Show all 9 1 /9 EU elections 2019 Europewide results EU elections 2019 Europewide results European People's Party group MEPs: 182 Vote share: 24.2% EU elections 2019 Europewide results Progressive Alliance of Socialists and Democrats MEPs: 147 Vote share: 19.6% EU elections 2019 Europewide results Alliance of Liberals and Democrats for Europe group MEPs: 109 Vote share: 14.5% EU elections 2019 Europewide results Greens–European Free Alliance MEPs: 69 Vote share: 9.2% EU elections 2019 Europewide results European Conservatives and Reformists MEPs: 59 Vote share: 7.9% EU elections 2019 Europewide results Europe of Nations and Freedom MEPs: 58 Vote share: 7.7% EU elections 2019 Europewide results Europe of Freedom and Direct Democracy MEPs: 54 Vote share: 7.2% EU elections 2019 Europewide results European United Left–Nordic Green Left MEPs: 38 Vote share: 5.1% EU elections 2019 Europewide results Non-Inscrits and other parties Non Inscrits (MEPs not affiliated with a parliamentary grouping): 6 Vote share: 0.8% Other parties: 29 Vote share: 3.9%

Juan Rodríguez Teruel, a politics professor at the University of Valencia, said that the election result showed Mr Sanchez’s clear mandate.

He said: “This clear vote of confidence in Sanchez’s leadership will allow him to present himself as the most powerful moderate head of government in any major European economy. The results complete PSOE’s comeback in Spanish politics, benefiting from the collapse of Podemos and the fragmentation of the right.”

However, the Spanish government faces being frustrated or embarrassed by pro-independence Catalan politicians, with the former president Carles Puigdemont and his ex-minister Antoni Comin securing EU parliament seats from self-exile in Belgium, alongside the imprisoned former vice-president Oriol Junqueras.

Mr Puigdemont, who hailed the result as “fresh impetus” for the movement and a testament to their “persistence”, has vowed to contest any ruling that forces him to return home in order to register as a Spanish MEP, which would lead to his arrest on charges relating to his short-lived independence declaration in 2017.

Mr Junqueras, currently on trial for rebellion, is likely to encounter similar obstacles but intends to launch a mainly symbolic campaign for the European Commission presidency, running as the candidate for the separatist and regionalist grouping European Free Alliance, which also includes the SNP and Plaid Cymru.

In Catalonia, a lower turnout compared to April’s parliamentary polls helped Puigdemont’s Junts per Catalunya (Together for Catalonia) and Mr Junqueras’ Esquerra Republicana (Republican Left) win a combined 49.8 per cent vote share, handing the pro-independence groups a victory to strengthen their resolve.

“Puigdemont has pulled off an overwhelming personal victory. He and Junqueras will have a share of the spotlight in Brussels over the coming months, attempting to take their legal case to the heart of the European Parliament,” said Mr Teruel. “For the first time, this will give legal attention to the Catalan question in the European sphere.”

Their headline coup came in the Catalan capital where Esquerra candidate Ernest Maragall became the first separatist Barcelona mayor, dethroning housing activist Ada Colau in a race decided by fewer than 5,000 votes, while former French prime minister Manuel Valls trailed Socialist Jaume Collboni in fourth place.

Yet, 76-year-old Mr Maragall – part of a dynasty comprising an ex-Catalan president and a celebrated modernist poet, surely making him the first mayor already to have a metro stop named after his family – fell short of a majority in the city hall, with 10 out of 41 seats and will now have to work with Ms Colau.

Despite losing the battle for the hegemony of the left, Ms Colau, the spokesperson for Barcelona en Comu (Barcelona in Common) which also won 10 seats, called for a coalition to be drawn up along traditional lines rather than over the independence issue, offering to lend her support to an “inclusive left-wing executive”.

Mr Valls, backed by unionist liberal party Ciutadans (Citizens), admitted that he “can’t claim to be happy with the nature of this result” but will complete a political comeback as a local councillor for his birthplace and has pledged to make Barcelona a European powerhouse rather than a sovereign capital.

Prime minister Pedro Sánchez welcomes Socialists' win in election

Meanwhile, the results were far rosier for PSOE in the other Spanish autonomous communities as Mr Sanchez delivered a second round of humiliating defeats for the conservative People’s Party (PP) following their collapse in the general election, finishing top of the polls in 10 of the 12 available regional assemblies.

The Socialists also increased their lead over Pablo Iglesias’s more hardline left-wing party Podemos (We Can), which is pushing for Mr Sanchez to form a national coalition between their parties, but may no longer carry enough weight.

Amid the growing prospect of governing alone and seeking deals on a case-by-case basis, Mr Sanchez is expected to spend the coming month negotiating on several fronts, including on the continental stage, asking for more Spanish representation in both the European Commission and European Central Bank (ECB).