A Russian dissident who is serving a 25-year prison sentence after criticising Russia’s war in Ukraine has written to his former Cambridge University College from Siberia where he is incarcerated.

Dual British-Russian citizen Vladimir Kara-Murza said in his letter to Trinity Hall that “the truth, in the end, does come out stronger”.

He said he was “incredibly honoured” to learn he had been made an Honorary Fellow of the College in recognition of his bravery, adding that “good news are a scarce commodity in a special-regime prison in Siberia”.

The 42-year-old, a journalist and opposition activist, was imprisoned in April 2022 and convicted of treason last year.

He is among a growing number of dissidents held in increasingly severe conditions under President Vladimir Putin’s political crackdown.

The UK Foreign Secretary, Lord David Cameron, last month called for Russian authorities to “release him immediately on humanitarian grounds”.

Mr Kara-Murza was last year made an Honorary Fellow of Trinity Hall, where he studied, in recognition of his bravery in speaking out on Russian foreign policy despite the clear danger.

The honour was accepted on his behalf by his wife, Evgenia.

Mr Kara-Murza addressed his handwritten letter to the College’s Master, Mary Hockaday.

He wrote: “Good news are a scarce commodity in a special-regime prison in Siberia, but I was so heartened and so incredibly honoured to learn that I have been inducted among this academic year’s Honorary Fellows at Trinity Hall.

“I would like to convey my most profound gratitude to you, to the College Fellows, and to the entire Trinity Hall family for this humbling recognition from my alma mater.

“It is often said that every historian subconsciously wishes to personally experience the period of his or her study – and, given that among my main topics at Cambridge was the history of the Soviet dissident movement, I suppose I really cannot complain.

“But being a historian also gives the advantage of having a larger perspective – and of being able to see beyond the next turn.

“If the dissident movement in the Soviet Union and other eastern European countries has taught us anything, it is that, however unpromising the odds may appear, the truth, in the end, does come out stronger.

“I look forward to staying in touch and to one day meeting you and joining fellow Trinity Hall members and alumni at our magnificent college, a place like no other.”

He signs off his letter, “Yours ever” followed by his signature.

Mary Hockaday, Master of Trinity Hall, said: “It was humbling to receive this message from Vladimir and wonderful to think that in some small way he was heartened by the news of his Honorary Fellowship.

“He was and remains an excellent historian as well as a courageous political campaigner.

“Trinity Hall aims to foster critical thinking and intellectual resilience in all its students and Vladimir exemplifies this with his reminder that times change and that a longer perspective can be a source of hope.

“However, in the immediate present, we continue to declare his imprisonment a travesty and we add our voice to all those calling for his release.”

Lord Cameron described Mr Kara-Murza last month as a “committed human rights activist striving for a democratic Russia, and an outspoken critic of the war in Ukraine”.

He said the dissident “was considered a threat by the Kremlin” and that “Putin locked him up in a bid to silence him”.

“Russia’s depraved treatment of political prisoners must end,” said Lord Cameron.

Mr Kara-Murza, who twice survived poisonings that he blamed on Russian authorities, has rejected the charges against him as punishment for standing up to Mr Putin.

He likened the proceedings to the show trials under Soviet dictator Joseph Stalin.

Mr Kara-Murza has been awarded a Pulitzer Prize for the “passionate columns” he penned for the Washington Post while in a Russian prison cell.