A Pakistani court on Tuesday declared the trial in jail of former Prime Minister Imran Khan on charges of leaking state secrets illegal, his lawyer said.

A special court has been conducting the trial in prison, citing security concerns, since Khan was indicted on the charges last month.

“Islamabad High Court has declared illegal the notification for jail trial,” said Naeem Panjutha, the lawyer, in a post on social media platform X.

An order declared all proceedings of the trial conducted since August 29 as void.

“The proceedings and the trial conducted in jail premises in a manner that cannot be termed as an open trial stand vitiated,” said the court order.

It said the jail trial orders by the government did not fulfil its legal requirements, adding that “in exceptional circumstances, and where it is conducive to justice, a trial can be conducted in jail in a manner that fulfils the requirement of an open trial or a trial in camera provided it is in accordance with the procedure provided by law”.

The ruling means the prosecution would have to restart the trial, either in open court or in jail after fulfilling those legal requirements.

Khan’s legal team had challenged the law ministry notification that ordered the trial to be held in prison.

The charges against Khan relate to a classified cable sent to Islamabad by Pakistan's ambassador in the United States last year, which Khan is accused of making public.

Former cricket star Khan, 70, who was forced from office in 2022 after losing a no-confidence vote in parliament, has had dozens of legal cases filed against him.

He has been convicted in one graft case and sentenced to three years in jail. The sentence was suspended by a court to allow his release on bail but he remains in prison in connection with other cases.

Khan says the dozens of cases are aimed at keeping him out of politics ahead of a February election in view of his differences with the powerful military generals.

The military, which has ruled Pakistan directly for significant periods since independence in 1947 and wielded influence over civilian governments at other times, denies engineering Khan's ouster.

The election is scheduled for February 8, 2024, when former three-time Prime Minister Nawaz Sharif, who returned from self-imposed exile last month, will find his biggest challenge is to wrest back supporters of Khan who, despite being in jail, remains popular.