An Istanbul court has formally arrested the city’s mayor, Ekrem İmamoğlu, on corruption charges, sending him to pre-trial detention on the day he is expected to receive his party’s nomination to run for president. The mayor of Turkey’s largest city and a rival of the president, Recep Tayyip Erdoğan, was jailed on charges of leading a criminal organisation, bribery, misconduct and corruption, along with dozens of his staff and municipal officials. The Istanbul mayor and at least four others also faced a separate set of charges accusing him of “aiding an armed terrorist group,” for cooperating with a leftwing political