A Scot who spent four years in an Indian prison has said he feels "betrayed" by the UK Government.

Billy Irving, from Connel in Argyll, was one of six Britons jailed in the country in 2013.

They had been working as security on an anti-piracy ship which was boarded after allegedly straying into Indian waters.

The group, known as the Chennai Six, were convicted of carrying unlicensed firearms and ammunition in October 2013 and jailed along with 29 other men.

They were released last month after a series of appeals and Mr Irving arrived home on Wednesday.

However, he said could "never forgive" the Foreign Office and accused the government of failing to do enough to help.

Mr Irving, from Paisley, Renfrewshire, told the Mail on Sunday: "We would have been freed much sooner if they had really engaged in our plight and fought for us. I feel disgusted and betrayed."

Mr Irving's fiancee Yvonne MacHugh, who campaigned for his release, described former foreign secretary Philip Hammond as "next to useless and uninterested at best".

She accused current incumbent Boris Johnson of "hypocrisy" for saying the Foreign Office had worked on the case "unstintingly".

"Billy and the other men would've been free two years ago if they had been truly there for us," she said.

Mr Johnson has also faced criticism over his handling of the jailing of charity worker Nazanin Zaghari-Ratcliffe in Iran.

Mr Irving described his ordeal - during which he contracted dysentery and lost three stone - as an "unbelievable nightmare".

He said he felt "robbed" of seeing his two-year-old son William grow up.

Mr Irving said: "To finally smell fresh air and feel cold, wet rain on my face is the most fantastic feeling in the world.

"Now I just want to get to know my son, focus on being a proper father and spend time with my family."

The UK Government said Mr Irving's case was raised more than 50 times at ministerial level and nine times with the Indian PM since October 2013.

A Foreign Office spokeswoman said: "The UK Government was delighted that the men were released and the foreign secretary also paid tribute to those who campaigned for them.

"The Foreign Office worked tirelessly behind the scenes to reunite these men with their families.

"This included lobbying on their behalf, visiting them in prison, updating their families and maintaining close contact with their legal team."