Six British former soldiers held in Indian jail after authorities claim their ship was carrying huge cache of illegal weapons The MV Seaman Guard Ohio was detained on 12 October Indian authorities say vessel entered Indian waters with weapons on board Ship is operated US firm specialising in maritime security and training Former Parachute Regiment member Billy Irving, 33, has been detained Mick Dunn, 27, has also been imprisoned since October Six former British soldiers are in an Indian jail after being arrested while providing anti-piracy protection to a US ship. The MV Seaman Guard Ohio was detained on 12 October and its crew, which includes Britons, Indians, Ukrainians and Estonians, have reportedly been held in Chennai since 18 October with Indian authorities claiming the vessel entered Indian waters with a huge cache of weapons on board. The ship is operated by AdvanFort, a private US firm specialising in maritime security, training and intelligence operations for shipping and had some 35 crew members on board. Detained: One of the men is former Parachute Regiment member Billing Irving, 33 and his girlfriend Yvonne MacHugh, (both pictured) 25, from Connel, northwest Scotland, is campaigning for his release Concern: Mick Dunn, 27, who also served in The Parachute Regiment in Afghanistan, Iraq and Northern Ireland has been detained since October Six of the men are British and their families are petitioning Foreign Secretary William Hague to intervene. One of the men detained is former Parachute Regiment member Billy Irving, 33 and his girlfriend, Yvonne MacHugh, 25, from Connel, northwest Scotland, is campaigning for his release. She told the Scottish Daily Record: 'They are being held on suspicion of committing offences under the Passport Act, Essential Commodities Act and the Firearms Act but they haven't been charged. They are trying to say they had illegal firearms but the company gave documentation to say that everything was above board. Obviously I worry every time he goes away, but nothing bad has ever happened before. Billy is just saying that he sends his love to us all and that he doesn't know anything.' She said she had three letters from her boyfriend through the British consulate, but was unsure if her letters had got through. Held: The MV Seaman Guard Ohio was detained on 12 October and its crew, which includes Britons, Indians Ukrainians and Estonians, have reportedly been held in Chennai since 18 October Another one of the men imprisoned is Mick Dunn, 27, who also served in The Parachute Regiment in Afghanistan, Iraq and Northern Ireland. His sister Lisa Dunn, 34, from Ashington, Northumberland, told The Times that her younger brother had phoned as he was being taken away. 'He said "We're all being arrested and we have been transported to the police station. I do not know when I will speak to you next.  Last month the BBC reported that the chief engineer of the Sierre Leone registered ship had attempted to take his own life while in jail. Police said others present in the cell prevented the man from taking his life - his nationality is not known. There have been differing accounts of why and how the ship came to be stopped. The Indian authorities say they intercepted the American ship when it was reportedly sailing off the coast of Tamil Nadu. But last month AdvanFort released a statement thanking 'Indian officials for providing a safe harbour for its vessel.' It said India's coast guard and police had allowed the vessel to enter the port to refuel and shelter from a cyclone which had hit India's eastern coast. It added that all weaponry and equipment on board was properly registered. A Foreign and Commonwealth Office spokesman told Mail Online: 'We can confirm the detention of six British nationals from the ship, MV Seaman Guard Ohio, on 18 October in India. We are providing consular assistance and are in touch with the local authorities. In June four Brits sailing a converted warship to Africa on what they describe as an 'anti-piracy' mission were arrested off Senegal. Armed marine commandos boarded their decommissioned fast attack gun ship Defender, which had two fearsome-looking cannons, and took them into custody in Dakar. The Senegalese authorities said the four - all ex-UK servicemen - were detained on suspicion of 'illegal activity'.