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“In other words, Mr Zuma, in law, has not finished serving his sentence. He must return to the Escourt Correctional centre to do so,” the Supreme Court of Appeal judgement read.

The court took issue with the department’s claim that Zuma’s sentence had ended when the appeal was still being heard.

It also found that the decision by the former national commissioner of correctional services to grant Zuma medical parole against the advice of the Medical Parole Advisory Board, a specialist body, was unlawful.

“On any conceivable basis, the commissioner’s decision was unlawful and unconstitutional. The high court was correct to set it aside,” the judgement said.

The Jacob Zuma Foundation did not immediately respond to a request for comment, while a spokesperson for the department of correctional services said the judgement was being studied and it would likely respond later.