THE FATBOY SHOW : Frail Besigye Photo Ignites Debate.

Besigye was charged in a military court with illegal possession of a firearm, threatening national security, as well as treason, which carries the death sentence. He denies the accusations.

The news about his health came hours after a cabinet minister said he had seen Besigye in jail. He urged him to resume eating and pledged to drop his military trial.

Another leading opposition politician, Bobi Wine, along with human rights activists, went to the prison on Monday to visit Besigye.

But Bobi Wine said that prison officers refused to let them see him as he was very weak.

"This man is actually dying. Dr Besigye is in a terrible state. He cannot leave his bed," Bobi Wine told reporters as he called for his release.

He added that Besigye's co-accused, Obed Lutale, "told us that Besigye collapsed this morning when they were trying to carry him out of his bed".