Six British private security guards, popularly known as the Chennai Six after their arrest from a ship sailing in Indian territorial waters in 2013, have won an appeal against their conviction from the top court in the south Indian state of Tamil Nadu. It is not yet clear when they will be able to return to their homes as the Indian authorities can still move a higher court against the decision of the Madras high court.

The UK nationals were working as guards on a Sierra Leone-flagged ship, operated by the US-based anti-piracy security firm AdvanFort, when they were arrested by the Indian Coast Guard on charges of illegally carrying firearms. The men -- John Armstrong, Nick Dunn, Ray Tindall, Paul Towers, Nicholas Simpson and Billy Irving -- have denied the charges, which were initially suppressed by the Madras High Court.

But India's Supreme Court -- the country's topmost court -- reinstated the charges and ordered trial by a lower court. They were sentenced to five years in jail in 2016 by a sessions court in the coastal city of Tuticorin, the BBC reports.

The MV Seaman Guard Ohio had on board a 10-man crew and 25 armed guards including the Chennai Six. They were charged under the Indian Arms Act 1956, which prohibits illegal possession of arms and ammunition. The vessel was seized by the Coast Guard for sailing in Indian waters without permission in October 2013. The ship had been in Indian territorial waters for nearly a month before it was intercepted.

The ship's crew had in their possession semi-automatic weapons along with more than 5,700 rounds of ammunition. The crew also included Ukrainian, Estonian and Indian nationals.

The Britons had argued that the weapons were lawfully carried for anti-piracy purposes and that their paperwork, issued by the UK, was in order. The Chennai Six are currently being held at the Puzhal prison in Chennai, the Guardian reported.

Families rejoice

The families of the men are overjoyed at the winning of the appeal. Lisa Dunn, the sister of Nick Dunn, described it as "the best news ever".

She said: "The longer it went on, as much as you still have an element of hope, and it does dwindle after having so many delays and setbacks. It will make all of our Christmases -- all of our dreams have come true today."

John Armstrong's sister, Joanne Tomlinson, expressed concern over their final release as they still need to get police clearance before they can return to their home country. "There are steps being taken to try to ensure that everything's in place. That they can come back as quickly as possible, but we don't have a time-frame for that yet."

Prime Minister Theresa May's official spokesman said that the UK government are "working with the Indian authorities to discuss the next steps".

Meanwhile, Foreign Secretary Boris Johnson described the development as "fantastic news" and said the case "has been a top priority for everybody" at the Foreign Office (FCO). "The FCO has worked tirelessly behind the scenes to reunite these men with their families. I share their delight and I hope they can return home as soon as possible," Johnson added.