Istanbul's powerful mayor Ekrem Imamoglu is President Recep Tayyip Erdogan's biggest political rival who has had hurdle after hurdle thrown at him to stop him making a bid for Turkey's top job.

After a sensational entry into politics in 2019 when he was elected mayor of Turkey's economic powerhouse, Imamoglu quickly became a key figure within the main opposition Republican People's Party (CHP).

But his career has been overshadowed by a string of what critics say are politically-motivated legal cases designed to cripple his plans to contest Turkey's 2028 presidential election.

The latest blow came Tuesday when Istanbul University revoked his degree -- a high-stakes move as Turkish presidential candidates must have a higher education diploma.

"The days are coming when those who made this decision will be held accountable before history and justice," Imamoglu wrote on X.

Widely seen as best placed to challenge Erdogan in 2023, Imamoglu didn't run after being hamstrung by an unresolved defamation conviction.

Since then, his legal woes have multiplied with three new probes targeting him this year alone. He decried them as........

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