An Egyptian criminal court has convicted the youngest son of the ousted Islamist president Mohammed Mursi on charges of drug possession and consumption, jailing him and a friend for a year. Abdullah Mursi, 20, was not in court when Judge Abdel-Rahman Ayad issued the verdict. He had been on bail since his arrest in March. Mursi and his friend were arrested after police suspected they were smoking hashish on the side of a road on the east edge of Cairo. He denied the charges. His family has dismissed the case as an attempt to tarnish their image and as part of a crackdown on Islamists. His father has been in jail since being ousted last year by the military following mass protests against him. He is also facing several trials on charges that include inciting murder and conspiring with foreign groups to destabilise Egypt. At least 22,000 have been arrested since the government crackdown on Mursi supporters and Islamists, all pending trials. Also on Wednesday, a coalition of Mursi allies, led by the Muslim Brotherhood, said its spokesman, Magdy Qarqar, had been arrested. The arrest was part of a government crackdown ahead of planned mass protests yesterday on the first year anniversary of Mursi's ouster. Four leading members of the coalition, called the National Alliance for the Defence of Legitimacy, were arrested a day earlier, accused of inciting violence. The coalition had called for rallies to begin on Wednesday, marching from 35 mosques around Cairo and heading to Tahrir square and other public spaces, on a day of "monumental rage". The coalition said the arrests were an escalation, and renewed the call for protests.