A British charity worker who was sentenced to five years in jail by a secret Iranian court has lost her final appeal against the ruling.

Nazanin Zaghari-Ratcliffe, a project manager at the Thomson Reuters Foundation, has been imprisoned in Iran since April, when she was arrested and accused of attempting to overthrow the regime. She was then sentenced to five years imprisonment in September.

Her husband, Richard Ratcliffe, says the Iranian authorities provided no information about the nature of the charges, and carried out her trial in secrecy.

“The lack of justice in Nazanin’s case continues to be a stain on Iran...it is a needless waste of a mother and child’s life for their own political bargains and economic interests," said Mr Ratcliffe on Sunday.

Earlier this month, Mrs Zaghari-Ratcliffe, 37, launched her final appeal against her sentence.

But the the Iranian news agency Mizanonline.ir published an article on Sunday which quotes prosecutor Abbas Jafari Dolatabadi as saying that her sentence has been finalized.

Mizanonline.ir is affiliated with Iran's judiciary.

It comes as the Iranian regime brought two fresh allegations against Mrs Zaghari Ratcliffe that she and the Thomson Reuters Foundation strongly deny.

Firstly, the court in Tehran claims she used to work as a recruiter for BBC Farsi, the broadcaster's Persian-language news service, which is banned in Iran.