Environmental organisation Greenpeace has announced the release of its Arctic Sunrise ship after being held for nearly a year by the Russian authorities.

The ship, dubbed Arctic 30, has left Murmansk port in Russia for its home port in Amsterdam, the Netherlands, where it will be assessed and repaired further.

In September 2013, the ship was taken into custody by the Russian authorities after two activists boarded a Gazprom’s Prirazlomnaya oil rig to protest against its oil drilling plans in the Arctic.

All the 30 campaigners and journalists on board the ship were initially charged with piracy.

The imprisonment of the ship and its crew sparked an outcry from people worldwide and prompted international pressure on Russia to free the activists.

Under a presidential amnesty in November 2013, Russia released all of the protesters from jail and expelled them from the country by reducing the charges to hooliganism, according to Russian news agency Itar-Tass.

In early June, a Russian investigative committee declared that the arrest of the icebreaker was invalid, following which a Greenpeace crew, led by captain Daniel Rizzotti, gained access to the ship on 27 June.

"The Arctic Sunrise is now headed for Amsterdam, where the ship will need to undergo extensive repairs, so that it can get back to protecting the Arctic."

However, the crew observed that the ship needs to undergo a series of repairs and subsequently spent more than a month to make the vessel seaworthy.

Greenpeace International Arctic campaigner Faiza Oulahsen said: "When the captain and crew boarded the Arctic Sunrise they found it in a bad state, with no maintenance for ten months, and the ship’s navigation, communications and safety systems either removed or destroyed.

"The Arctic Sunrise is now headed for Amsterdam, where the ship will need to undergo extensive repairs, so that it can get back to protecting the Arctic from reckless oil companies like Shell and Gazprom."

Despite dropping criminal cases and releasing all 30 captured campaigners, the Russian investigative committee has extended the investigation of the incident until 24 September.

"The illegal boarding and arrest of the Arctic Sunrise and the on-going investigation into the Arctic 30 protest was an attempt to intimidate and stifle debate about Arctic oil drilling, but it has only made us stronger," Oulahsen added.

"Millions of people spoke out against the illegal imprisonment of the Arctic 30. These same millions of people know the planet is warming and that Arctic ice is melting, and will continue to peacefully oppose the reckless pursuit of Arctic oil both in Russia and around the world."

Image: The Greenpeace ship Arctic Sunrise in the Northern Sea Route (NSR) off Russia’s coastline. Photo: courtesy of Will Rose / Greenpeace.