Thousands of ​Turks gathered in central Istanbul on March 18 for a protest held exactly 12 months after Ekrem Imamoglu, President Recep Tayyip Erdogan’s chief political rival, was jailed after a dawn police raid on his home.

Imamoglu, 55, faces a raft of corruption charges, described as fabricated and trumped-up by Erdogan critics. They could lead to a prison sentence of 2,000 years or more. Red CHP opposition party banners and Turkish flags were waved outside Istanbul city hall as speeches demanding freedom for Imamoglu were heard. "Rights, law, ​justice," the crowd chanted as Imamoglu's wife spoke at the event.

Imamoglu was deposed from his post as Istanbul mayor after he was indicted. The chief prosecutor who led the investigation against him, Akin Gurlek, was in mid-February made justice minister, sparking a brawl and other ugly scenes in parliament. The CHP, meanwhile, is itself subject to an ongoing massive judicial crackdown.

Imamoglu remains the CHP's presidential candidate, though his predicament as a defendant means he may not be able to run in the next election, which could come as early as next year.

CHP leader Ozgur Ozel told Reuters he believed Erdogan wanted the CHP to withdraw Imamoglu's candidacy. He said it would not, pointing to how 15mn people have expressed their support for him as a candidate.

“Erdogan ​is using the courts to get rid of his rival. There is a price to pay ​for this,” Ozel said in an interview last week.

"The next general elections are a referendum on whether democrats or autocrats will rule," ​Ozel added. "If we win, a very strong democracy will be built."