A judge has adjourned the case of 26 crew members of a crude tanker who have been held for more than six months in a controversial oil theft case.

The crew of the Ray Car Carriers-owned 300,000-dwt Heroic Idun (built 2020) are being held on bail on board the vessel off the coast of Nigeria as lawyers try to thrash out a deal to bring them home.

The men, mainly from India and Sri Lanka, are accused over an alleged attempt to illegally lift oil from an offshore terminal, but the owners, charters, insurers and global shipping bodies insist they have done nothing wrong and should be freed.

The International Chamber of Shipping, which represents 80% of the world’s merchant fleet, has described the detention of the men as “unacceptable” and called on Nigeria to release them.

The latest hearing in the case was on Monday in Port Harcourt but was adjourned until 24 March, according to the crew’s legal team.

The men are being held under armed guard by naval officials on the ship but have been allowed to speak to their families and lawyers through video conferencing.

The Heroic Idun was detained days after leaving the Akpo oilfield off Port Harcourt in August last year after the master mistook an approaching Nigerian naval vessel for a pirate ship.

The crew were held by Equatorial Guinea for three months before being taken on their ship to Nigeria.

All 26 have denied charges of attempting to lift oil without a licence and an offence under the Suppression of Piracy Act.

The delay means the case will not be resolved before the first round of voting in the Nigerian election on Sunday.

The current government of President Muhammadu Buhari had ordered security agencies to crack down on rampant oil theft.