The Neilston mum whose ex-soldier partner has languished in a notorious Indian prison for three years on arms charges says he has handed her definitive proof that he is innocent.

Yvonne McHugh, 27, broke the news after returning from a harrowing trip to Chennai (formerly Madras), where her partner Billy Irving has been imprisoned in hellish conditions since 2013.

Billy, a former trooper in the elite Parachute Regiment, had been working as a security guard on the American-owned anti-pirate vessel Seaman Guard Ohio.

Forced to put into port, the vessel was boarded by Indian authorities who found arms and ammunition - designed to be used, if needed, against the pirates which infest the Indian Ocean, preying on merchant shipping.

Billy was sentenced to five years imprisonment – and fined 3,000 Rupees (about £30) - along with five other British ex-soldiers and 29 other shipmates, on what thousands of his supporters consider to be trumped up charges.

Yvonne said of the Indian justice system: “They've ruined an unimaginable amount of people's lives by dismissing important and overwhelming evidence proving the men's innocence.

“Billy passed on his (arms) licences to me during our visit in the hope I'd share them with the world.

“They have been handed into the Indian courts - if they are again dismissed it could not be clearer now that the men are been held there illegally.

“We are clinging onto every single bit of hope that the Indian police can admit they made a mistake, free our boys and allow us all to move on from this nightmare”.

In a bizarre sequence of events the charges against Billy and the other men were scrapped by India's High Court, then reinstated after a challenge by the south-Indian Tamil Nadu authority, which has refused to back down over what the families see as a travesty of justice.

After the first 1,000 days of their ordeal in brutal and primitive Puzhal Prison the men's families lobbied Parliament and handed over a petition bearing 372,000 names.

An approach by a senior Roman Catholic clergyman to his counterpart has also failed to win any relief for Billy or the other men.

Meanwhile Argyll and Bute MP Brendan O'Hara, who has waged a vigorous campaign to free Billy (originally from his area) and the other men has accused the Foreign and Commonwealth Office (FCO) of failing to take effective action.

A FCO spokesperson said: “Our staff in India and the UK remain in regular contact with all six men and are continuing to support them and their families, working to make sure their

welfare is protected in prison. We recognise what a difficult time this is for those involved.

“We cannot interfere with India’s independent legal system, just as other countries cannot interfere with ours, but we will continue efforts to make sure this case is resolved swiftly.

“Ministers will continue to raise this case at the highest levels.”

Yvonne has described how on every day she was allowed to visit Billy in prison he brought with him a present for William.

With almost no resources but considerable ingenuity he managed to make a helicopter, a tank and a plane to amuse his son.

Yvonne wrote on Facebook: “Today was our last visit with Billy in prison. Our last visit of this trip and hopefully our last ever.

“Billy has shown incredible strength, resilience throughout this whole ordeal, I for one could not be prouder of him, and I know his parents and brothers feel exactly the same.”

She added: “At the very end of our visit today, William gave Billy a kiss as he carried him out to the front door of the prison.

“Billy looked at William and said “You take care of Mummy until I get home OK?” and William nodded then gave Billy another kiss. I literally cannot describe how beautiful a moment that was.

“Billy passed on his thanks to everyone for their support, and we both parted knowing one day, hopefully in the near future, we'll be together again.”