More than 100 MPs and peers have written to the foreign secretary calling for “quick and decisive” action to secure the release of a Scottish Sikh man in prison in India.
Jagtar Singh Johal, from Dumbarton, was arrested in November 2017 in connection with terror-related offences.
He has not been convicted of any crime and in March was cleared in one of nine cases against him.
The Foreign Office has been approached for comment and has previously said the UK government remains committed to working for faster progress on the case.
Mr Johal’s family and legal team had hoped India’s Supreme Court would issue a ruling on Thursday on whether he would be granted bail but they say there was no decision and no timeframe for the matter to be resolved.
Mr Johal is accused of being a member of a terror group, the Khalistan Liberation Force (KLF), which has carried out attacks in the Punjab region.
The charges against him stated that he travelled to Paris in 2013 and delivered £3,000 to other KLF figures, with the money then used to purchase weapons which were used in a series of murders and attacks against Hindu nationalist and other religious leaders across 2016 and 2017.
Mr Johal claims he was tortured in the early days of his detention and forced to make a confession.
The letter to Foreign Secretary David Lammy has been signed by cross-party MPs and peers.
It says there is a “window of opportunity” to secure Jagtar’s release following his acquittal in one of the cases against him.
The letter says: “The judgement on the evidence led is crucial and relevant to securing his release, because it is the same evidence that exists in the other outstanding federal court cases.”
The 38-year-old’s family says the Lammy has agreed to meet them on 8 May.
They have repeatedly called for the UK government to do more to secure his release through diplomatic channels with the Indian government.
Mr Johal’s brother Gurpreet Singh Johal, who is also a Labour councillor, said: “I’m glad the foreign secretary is meeting me again, as it shows he recognises that this is a make-or-break moment for Jagtar.
“The case against my brother has been tested in court and rejected, but the Indian authorities will keep him in prison for decades if the UK government doesn’t act to secure his release.
“We’ve seen that today at the Supreme Court – just the latest in an endless series of delays. This is the moment of truth for David Lammy: will he live up to his promises, or will he fail Jagtar like the last six foreign secretaries did?”
Dan Dolan, deputy executive director of the non-governmental organisation (NGO) Reprieve, said it was time for the government to act.
He said: “The previous UK government wasted years of Jagtar Singh Johal’s life, hiding behind the fiction that due process is possible in a case based on a torture confession.
“This is a politically motivated prosecution of a young British human rights defender, and the process is the punishment.”
The letter to Lammy was issued by the Labour MP for Jagtar’s constituency, Douglas McAllister, who said the cross-party support was very significant.
He said: “The failure to grant bail to my constituent, Jagtar Singh Johal, serves to demonstrate the need for greater urgency by the foreign secretary and the UK government to secure my constituent’s immediate release and his return to his family in West Dunbartonshire.
“I will be advising the foreign secretary when we meet next week of the strength of feeling across both houses that now is the time to act.”
The Indian government has repeatedly denied that Mr Johal was mistreated and has said due process has been followed in the case against him.
