Six former soldiershave been held in an Indian jail in dire conditions whilst a string of appeals have been pending in Indian courts, Beith said.
They were all working on a ship offering protection to commercial shipping against pirates operating in the Indian Ocean and are appealing convictions for possession of illegal arms.
Beith said: "The Prime Minister has an opportunity this week to raise the issue personally at the highest levels in India, and she needs to do so. There have been significant delays in the justice system, which are unacceptable.
He added that the men, including Nick Dunn from Ashington, were "working legally to protect ships from piracy but despite the evidence provided by the British government they have been kept in terrible conditions".
There are serious concerns about their physical and mental health, he said.
"The Prime Minister must demand that the appeal hearings are held without any further delay," he said.
Disclaimer: No Business Standard Journalist was involved in creation of this content
