A British resident has been sentenced in absentia by a court in Bahrain for allegedly trying to overthrow the government.

Ali Mushaima, a UK based activist who recently staged a protest on the roof Bahrain Embassy roof in London, was convicted alongside seven others today in a closed trial that has illustrated growing tensions between Bahrain and its neighbour Iran.

Bahrain’s ruling family – the Sunni led al-Khalifa dynasty – accuses its Shi’a neighbour Iran of backing protests which have swept the Gulf kingdom for more than a year and led to the deaths of at least 80 people.

The majority of Bahrain’s demonstrators are from the country’s Shi’a community who have long felt excluded and discriminated against by the ruling elite. Both the protesters themselves and Iran deny having any involvement with each other.

Today's convictions are likely to further raise tensions between Manama and Tehran which has been vociferously critical of the crackdown against pro-reform groups.

In total eight people were sentenced for up to 15 years in prison for plotting to bring down the country’s monarchy with the help of a “foreign country” – a clear reference to Iran.

According to the Bahraini government the defendants were accused of being part of an “Iranian backed terror cell” who were planning to conduct attacks on targets inside Bahrain including the Interior Ministry and the King Fahd causeway which links the kingdom to its staunch ally Saudi Arabia.

Five defendants were arrested in November by police in Qatar who extradited them to Bahrain. Three other defendants, including Mr Mushaima, were convicted in absentia. They all denied the charges.

It is not clear what role Mr Mushaima is accused of playing in the plot. The 29-year-old activist is a prominent figure in Bahrain’s London-based opposition movement and is loathed by the Bahrain government which is becoming increasingly frustrated at how Britain has become a hotbed of pro-reform support.

As well as his recent occupation of the Bahrain embassy, he has conducted periodic hunger strikes outside the American embassy in protest at Washington’s continued support for Bahrain which remains home to the US Navy’s 5th Fleet.

His father is Hassan Mushaima, a prominent Shi’a cleric and opposition leader who returned to Bahrain last year and was promptly sentenced to life in prison by a military court after widespread protests broke out against the ruling regime. His son was convicted alongside him in absentia.

Mr Mushaima did not answer his telephone yesterday but he has previously denied any links to Iran, stating that he is simply an opposition supporter who has been unable to return to Bahrain because of political persecution.