European Commission First Vice-President Frans Timmermans delivers a speech during a debate on the rule of law in Romania at the European Parliament in Strasbourg, France, October 3, 2018. REUTERS/Vincent Kessler

BRUSSELS (Reuters) - Frans Timmermans, the deputy head of the European Union executive, launched a bid to succeed his boss Jean-Claude Juncker next year, saying on Wednesday he would seek to lead the center-left campaign for May’s European Parliament elections.

Speaking in his Dutch home town, the country’s pugnacious former foreign minister, said he hoped to run a “beautiful and optimistic campaign” in defense of a European Union which he has helped see through several crises since European Commission President Juncker made him his first vice-president in 2014.

In a statement issued by his Dutch Labour Party, the 57-year-old spoke of reaching out to the majority of Europeans who did not exercise their EU vote last time and opposing “blackmail” from big corporations seeking “unfair tax deals”.

Timmermans, whose fluency and passionate speaking style in German, English, French, Italian and Russian, may make him a formidable campaigner across the continent, stands a good chance of winning the formal backing of the center-left Socialists and Democrats (S&D) group in the EU.

However, his prospects of becoming Commission president when Juncker steps down next November are less clear. Polls show the left struggling across Europe and the way in which national leaders will nominate Juncker’s successor is not yet agreed.

The center-right European People’s Party, which polls indicate could remain the biggest block, is set to choose either German EU lawmaker Manfred Weber or former Finnish prime minister Alexander Stubb to lead its campaign next month.

But many national leaders reject pressure from the European Parliament for them to nominate a winning party leader as the successor to Juncker, saying the want to have a free choice next June on who they decide to put forward to run the EU executive.