The call, from East Renfrewshire MP Kirsten Oswald, follows new demands for justice from Billy’s brother Jamie, from Bearsden.
He has welcomed news that Prince Harry is backing the campaign to free all six men incarcerated in a squalid prison in the Indian state of Chennai.
Billy is a former UK soldier who was arrested on firearms charges in 2013 after the anti-piracy ship on which he was working as a security guard strayed into Indian waters.
After a bizarre and labyrinthine court process the ex-Para, and five colleagues, was first freed and then re-arrested and sentenced to five years in prison.
His partner Yvonne, from Neilston, has made the harrowing trip to visit him, and has led the campaign to have him freed.
She has papers which she says prove that the supposed illegal arms found on the ship were held legally, and is horrified that Billy and his colleagues, whose role was to protect the sealanes from Somali pirates, has been caught up in what many see as turf war over legal jurisdiction between the Indian national government and Chennai, a devolved state.
So far none of the high profile support or lobbying has had any effect on the Indian authorities, and the Foreign and Commonwealth Office have been unable to win any form of reprieve.
Conditions in the prison are said to be appalling and a breach of basic human rights.
Now East Renfrewshire MP Kirsten Oswald is urging Boris Johnson to put an end to what she sees as a scandal that demands robust intervention.
Together with Yvonne she met FCO staff and stressed both the increasing urgency of the situation and concerns about an incident in one of the imprisoned men was being held in a mental his hospital and medicated against his will.
Kirsten said: “It was useful to speak with the FCO staff on this issue, but sadly there seem to be no further answers forthcoming on Billy’s case.
“I have continued to press for his release and lobbied the UK Government relentlessly to explore every diplomatic channel to get Billy home with his family.
“What we require now is some action from the Foreign Secretary, Boris Johnson, to put pressure on the Indian authorities and bring these innocent men home, where they belong”.