Iran’s Guardian Council on April 20 disqualified ex-president Mahmoud Ahmadinejad from running in the upcoming May 19 presidential election, opting for a field of six that is likely to be dominated by incumbent moderate President Hassan Rouhani and hardline cleric Ebrahim Raisi.

Iranian state TV carried news of the decision, announcing that the outspoken and polarising Ahmadinejad, president from 2005 to 2013, a populist who had been publicly advised by Supreme Leader Ayatollah Ali Khamenei not to attempt to run, had been barred from the contest.

“It plays relatively well for Rouhani,” Dina Esfandiary, a fellow at the Centre for Science and Security Studies at King’s College London, told Bloomberg. “[Tehran Mayor Mohammad Baqer] Qalibaf and Raisi are likely to split the conservative vote, whereas on the other hand Rouhani is uniting the moderates; he is the candidate that is bringing them together.”

Apart from Rouhani, Raisi and Qalibaf, the Guardian Council also approved the candidacies of First Vice-President Es’haq Jahangiri – thought to be contesting the election simply to protect Rouhani in the debates over his post-nuclear deal economic record and expected to pull out of the race just before the polling day – and former conservative culture minister Mostafa Mirsalim and Mostafa Hashemi-Taba, a former minister of industry, affiliated to pro-reform groups.

The Guardian Council, a constitutional watchdog, held its meeting to decide the candidates in the holy city of Qom rather than Tehran. The Financial Times said on April 21 there had been disagreements at the highest echelons of the political hierarchy over allowing Rouhani to compete, with the vote equal at six votes for his candidacy and six against before the deadlock was broken.

The top challenger to Rouhani is set to be stern-faced Raisi, 56, appointed last year to manage the billion-dollar foundation Astan Quds Razavi – an Islamic charity that controls the country’s holiest shrine in the northeastern city of Mashhad. He is thought to have the backing of the 77-year-old supreme leader, whom some analysts believe he is odds-on to eventually succeed. Raisi has attacked the persistent high unemployment that Iran is experiencing.

When Ahmadinejad was re-elected in 2009 there were widespread allegations of ballot box fraud, triggering the biggest street demonstrations in the Islamic Republic since the 1979 Islamic Revolution.

Unconfirmed reports say Ahmadinejad has already faced curbs on his political activities after threatening to mobilise the poor to disrupt the election if he were to be disqualified. Local media said security and police personnel had established a high-profile presence in neighbourhoods close to his in home in eastern Tehran. And Iranian police fanned out across Tehran after the names of the candidates were announced, reported the news site of the Iranian judiciary Mizan Online.