Medical experts have also scuppered his bid to avoid trial on the grounds of poor health.

Mngeni was diagnosed with a brain tumour last year. Medical records showthat the tumour had spread "extensively along the lining of the spinal cord and the brain".

But yesterday his lawyer, Qalisile Dayimani, said the neuropsychologist's report had declared Mngeni fit to stand trial.

Anni was shot dead while on honeymoon with her husband, Shrien Dewani, in Cape Town in November 2010.

Mngeni and Mziwamadoda Qwabe were arrested after shuttle operator Zola Tongo implicated them. Tongo confessed that Dewani had offered him R15000 to find hitmen to kill Anni.

He said he then hired Mngeni and Qwabe to carry out the hit. Tongo is serving an 18-year jail sentence. Qwabe entered a plea and sentencing agreement with the state and revealed in a chilling confession how Mngeni shot Anni.

Cape Judge President John Hlophe sentenced him to 25 years' imprisonment on Wednesday in the Cape Town High Court.

"I was arrested by the police on November 18 2010 and on that same day I confessed my involvement to the police," Qwabe said.

"I also did a pointing-out the next day, where I pointed all the material places to the police including the drain into which I threw the bullet casing as well as where I threw the yellow gloves away. The police retrieved the bullet casing in my presence. I also assisted the police to recover the firearm used during the incident."

Mngeni has pleaded not guilty.

Dayimani said Qwabe's confession had thwarted his preparations for defending his client.

"Qwabe is not setting out everything in his plea agreement. I think the state will now make an amendment to the indictment," said Dayimani. "They indicated to me that they want to take a detailed statement from him, which they will have to disclose to us."

Last month, the matter was postponed at Dayimani's request so that Mngeni could be examined by a neuropsychologist because he suffered from "double vision" and headaches. He said he feared he might not be able to follow the court' proceedings.

Mngeni will go on trial on Monday.