Boris Johnson has, for the first time, said the Indian government is arbitrarily detaining Dumbarton man Jagtar Singh Johal.
The prime minister made the statement in a letter to Labour leader Keir Starmer.
The letter describes Jagtar, known as Jaggi, as a British national who has been “arbitrarily detained in India for the past four and a half years”.
He goes onto say that UK ministers and officials have raised concerns directly with the government of India about Mr Johal’s case on almost 100 occasions.
Keir Starmer has previously written to Boris Johnson asking why the UK Government hasn’t followed the UN, saying: “On behalf of Jagtar’s family, I’d like to ask when they can expect your government to make the request?”
Almost five years on, Jagtar has not stood trial in any of the cases against him and alleges he was beaten, electrocuted and tortured while in initial custody.
Bhai Amrik Singh, the chair of the Sikh Federation (UK) said: “Finally Boris Johnson has been forced to admit Jagtar Singh Johal is being arbitrarily detained in a jail in India.
“The UK government probably reached this conclusion within weeks of his arrest and torture in November 2017, but has failed to acknowledge this publicly fearing India’s reaction.
“Boris just met Narendra Modi at the G7 Sumit, but only admitted this now in response to Keir Starmer’s letter as he would have had pressure to call on Modi for Jagtar’s immediate release and return to the UK.
“We understand Liz Truss recently met her Indian counterpart in Rwanda and also failed to raise Jagtar’s case.
“We have decided to increase the pressure on the UK government by calling a mass Sikh lobby of Parliament in mid-July so constituents for hundreds of MPs can raise Jagtar’s plight.”
Jagtar Singh Johal, a Sikh activist, has been locked up without trial since November 2017. He is accused of being part of a terror plot against right-wing Hindu leaders.
In May, a UN working group said Mr Johal’s detention was arbitrary and concluded he should be released immediately.
A spokeswoman for the UK Foreign and Commonwealth Office said: “We consistently raise our concerns about Mr Johal’s case with the government of India, including his allegations of torture and mistreatment and his right to a fair trial.”