Salman, who headed the now-outlawed Al-Wefaq movement, was convicted in November for “acts of hostility” against Bahrain and “communicating with Qatari officials … to overthrow constitutional order”, – a ruling human rights groups have called a travesty and Qatar has repeatedly denied.
His aides Ali al-Aswad and Hassan Sultan, who had been sentenced to life in absentia, also lost their right to appeal.
According to a statement released by the public prosecutor on Monday, the Supreme Court confirmed the verdict against Salman and his aides for “spying for a foreign state in order to … overthrow the government”.
The London-based Bahrain Institute for Rights and Democracy condemned the ruling and challenged Bahrain’s allies for supporting its leadership.
“This is political revenge and an insult to justice,” Sayed Ahmed Alwadaei, the group’s director of advocacy said.
“Punishing peaceful dissidents for leading protests against the corrupt ruling family has nothing to do with justice. This verdict shames Bahrain’s rulers and their allies in traditional Western democracies, namely US and UK.”
Salman, who is in his 50s, has long been targeted by Bahrain’s government. According to the United Nations, when he was first arrested in 1994, he was allegedly tortured and detained for months without trial before being deported and forced to live in exile for more than 15 years.
The prominent figure is currently serving a four-year sentence on charges of “denigrating and disparaging the interior ministry,” inciting others to break the law and inciting hatred against naturalised Sunni citizens, many of whom serve in Bahrain’s security forces.
Human rights groups have frequently said the cases against activists in Bahrain – men and women, religious and secular – fail to meet the basic standards of fair trials.
Since the Bahraini authorities crushed street protests in 2011, demonstrators have clashed frequently with security forces who have been targeted by several bomb attacks.
Lama Fakih, the deputy director of the Middle East and North Africa division at Human Rights Watch, said the court ruling was part of a broad strategy employed the Bahraini government “to fight against freedom of expression in the country”.
“The judiciary has been used to impose the rule of the regime and to ensure that all critics are stamped out.
“We’ve seen the Bahraini government not just arbitrarily detain dissidents but also abuse them in detention, in some cases strip them of their citizenship, ban them from travelling. They’ve also banned all opposition parties and free media in the country.
“This is part of its widespread strategy to stamp out any kind of legitimate dissent”.
Bahrain, along with Saudi Arabia and the United Arab Emirates (UAE), severed all ties with Qatar in 2017, banning their citizens from travel to or communication with the fellow Gulf Cooperation Council (GCC) member.
Ruled for more than two centuries by the Sunni Al-Khalifa dynasty, Bahrain has been hit by waves of unrest since 2011, when security forces crushed Shia-led protests demanding a constitutional monarchy and an elected prime minister.
Bahrain’s two main opposition groups – Al-Wefaq and the secular Waad – are prohibited from representation in parliament.
Bahraini authorities accuse Shia-dominated Iran of provoking unrest in the kingdom. Tehran denies the allegation.