LONDON — A former Iranian member of Parliament who has been jailed for more than three months without charge has claimed his interrogators are torturing him and attempting to turn him into a “mental patient.”

Ali Akbar Mousavi Khoini, who, as a member of Iran’s reformist bloc was highly critical of his country’s detention practices, was arrested at a rally calling for the elimination of legal discrimination against women in Iran on June 12. Since then, he has been held at Tehran’s Evin prison with no access to lawyers.

“I am being tortured,” Mr. Khoini shouted to bystanders when he was released briefly to attend a memorial service for his father, who died last month.

“They wake me up in the middle of the night to interrogate me. They are trying to turn me into a mental patient.”

Mr. Khoini, 36, said he was being held in solitary confinement, with his hands and feet chained, and interrogated four times a day as his captors urged him to “repent” for his criticism of human rights abuses by the country’s judiciary and intelligence services.

As a politician between 2000 and 2004, Mr. Khoini regularly visited prisons to expose what he called inhumane practices before he was disqualified by conservative clerics from seeking reelection.

Calls seeking comment from Iran’s embassy in London were not returned yesterday.