Media playback is unsupported on your device
Media captionNewsnight spoke to Ghoncheh Ghavami's brother, Iman in September

A British-Iranian woman detained at a men's volleyball match in Iran has been sentenced to a year in prison, her lawyer says.

Ghoncheh Ghavami, 25, was found guilty of spreading anti-regime propaganda, lawyer Alizadeh Tabatabaie said.

Iran banned women from volleyball games in 2012, extending a long-standing ban on football matches.

The Iranian authorities have argued that women need protection from the lewd behaviour of male fans.

Britain's Foreign Office said it was concerned about the sentence.

"We have concerns about the grounds for this prosecution, due process during the trial, and Miss Ghavami's treatment whilst in custody," it said in a statement.

Amnesty International has described Ms Ghavami, who is from Shepherd's Bush in west London, as a prisoner of conscience, and called for her immediate release. More than 700,000 people have signed an online petition urging the authorities to free her.

The graduate of the University of London's School of African and Oriental Studies was part of a group of women who tried to watch Iran play Italy in a match on 20 June.

The women were arrested and allegedly beaten before being freed.

Ms Ghavami was rearrested later and subsequently put on trial. She launched a hunger strike in October after being held in isolation cells.