Protests at UK petrol stations in support of Greenpeace activists held in Russia

Protesters will gather at more than 70 Shell petrol stations across the UK today as part of Greenpeace's campaign to free a group of activists arrested in Russia.

Two journalists and 28 Greenpeace activists are being held in St Petersburg charged with piracy and hooliganism after Russian authorities seized the Arctic Sunrise vessel in September.

Demonstrators will be asking members of the public to show their support for the 30 - six of whom are UK nationals - by sending a message to the Russian Embassy in London asking for their release, Greenpeace said.

They will also be asking for signatures on a petition asking the fuel giant to pull out of its "risky and reckless joint venture with Gazprom to drill for oil in the Arctic Ocean".

Greenpeace UK executive director John Sauven said: "Shell were thrown out of the Alaskan Arctic by the US government following a series of blunders and accidents culminating in the grounding of their drill rig. Then Shell opted for the more flexible regulatory environment of the Russian Arctic, and went into partnership with Kremlin-owned Gazprom.

"Gazprom, who managed a spectacular 827 oil spills in 2012 alone, are possibly the only company to make a bigger mess of their Arctic operations than Shell. It was a reckless Gazprom adventure into the Arctic that the Greenpeace ship, Arctic Sunrise, was sent to peacefully expose. Gazprom responded by calling in the security forces.

"Shell cannot operate safely in the Arctic. They're taking huge unnecessary risks with both the environment and their reputation. Its time they quit their links with Gazprom before the damage becomes irreversible."

Greenpeace said Russia's investigative committee had announced it was applying for an extension to the detention of the 28 campaigners and two freelance journalists while it continues its inquiries.

The organisation said hearings over the extension bid must be completed by November 24.

Sir Paul McCartney has written a personal letter to Russian president Vladimir Putin calling for the release of Greenpeace activists.