LONDON 

The British government sanctioned Russian judges and prosecutors on Monday who are involved in the trial of dual British national Vladimir Kara-Murza, an opposition politician and Kremlin critic. 

Three judges and two prosecutors as well as an "expert witness" have been sanctioned for their roles in the sentencing of Kara-Murza, who is facing 25 years in a penal colony after the rejection of his appeal, the Foreign Office said in a statement.

In the statement, British Foreign Secretary James Cleverly said the rejection of Kara-Murza’s appeal shows Russia's "complete disregard for human rights and freedom of expression."

Saying that today's sanctions send "a clear message that the UK will not stand for this treatment of one of its citizens," he called on Russia to release him "immediately and unconditionally."

Last month, the European Council also blacklisted nine Russians in response to Russia's 25-year prison sentence against Kara-Murza.

In April, a Russian court sentenced Kara-Murza to 25 years on charges of treason, spreading "false information" about the Russian military, and leading an "undesirable" organization.