A memory card smuggled out of a Russian jail in a match box and a letter from Beatles icon Sir Paul McCartney to Vladimir Putin helped end an international scandal.
That might sound like a plot in a Hollywood movie, but it is actually the reason why British Greenpeace activists are not rotting in a Siberian prison.
In 2013 a group of 30 environmentalists from around the world, including five Brits, set their sights on a Russian oil company, Gazprom, that was about to start drilling in the Barents Sea.
Their plan was relatively simple, attach a pod to the side of the oil rig which they could protest from, not only would they halt production, they’d draw the world’s attention to the impact of fossil fuels and stop what they believed was an international oil rush in the Arctic.
But instead they were shot at by the Russian coastguard and caught up in a scandal after their ship was raided by gun-toting counter-terrorism soldiers and the entire crew arrested on piracy charges, jailed for two months with the threat of a further 15 years behind bars.
Now the dramatic inside story on how their environmental mission turned into a nightmare is being told for the first time in a new six part BBC Two series, On Thin Ice: Putin v Greenpeace, which starts on Sunday.
Using incredible unseen footage captured by the protestors and testimony from many involved, the series lifts the lid on what was really going on behind the headlines.
Ben Stewart, who was head of communications for Greenpeace at the time, was drunk and raving in a London nightclub when he received a panicked phone call from aboard their ship, the Arctic Sunrise.
The crew had been shot at trying to carry out their mission and were now under attack.
A helicopter carrying heavily armed and balaclava-clad Russian solders was attempting to land on their ship and they knew they were in serious danger.
While the crew had locked down as much of the ship as possible to hold off the attack, it was only a matter of time before they lost control and were cut off from the outside world.
Action co-ordinator Frank Hewetson, 58, who has been with Greenpeace for 30 years, managed to make a call before it was too late.
Ben said: “My phone started ringing and I looked at it, it had this 15-digit number that I didn’t recognise, it was like a barcode or something.
“I just heard Frank trying to convey information as quickly as he could. And he said, ‘there’s about 20 of them, they’re special forces, they were heavily armed’, you knew s**t was going down.
“He sounded deeply adrenalised, I was deeply drunk and sobered up very, very quickly.
“This was a gross overreaction by the Russians, but also what they’ve done is not legal.”
Ben felt guilty, just weeks previously he’d been set to go on the mission but had to pull out at the last minute.
He was replaced by 27-year-old Brit Alexandra Harris from Exeter, and it was her first protest for Greenpeace.
Not wanting to scare her parents, she’d told them she was going to the Artic to research polar bears.
Instead, she found herself at the centre of the drama.
Alexandra said: “It’s like finding yourself in the middle of a James Bond movie. I was terrified.
“I’ve never had a gun pointed at me before.
“We were all taken down to the bottom of the ship, put in the mess, they searched us to make sure that we didn’t have anything on us like mobile phones, footage, that kind of thing.”
Little did they realise that former cameraman Phil Ball had recorded everything and managed to hide the camera in his pants before carefully stuffing the memory card in the sole of his boot.
Miraculously, even after being banged up behind bars, the Russians never discovered it.
And Phil managed to get the memory card smuggled out of prison hidden in a matchbox he gave to his interpreter.
For Brit Frank Hewetson, storming an oil rig in the middle of the sea was nothing new.
The 58-year-old is banned from entering America and Greenland after staging multiple protests for Greenpeace against oil companies around the globe.
But this experience pushed him to the brink of a nervous breakdown as he struggled to cope behind bars, locked in the same cell with a double killer and the head of a Russian taser gang.
He said: “It was an incredibly daring mission. It needed to be done. But the plan, I think you could say, went to s**t!
“I felt a mixture of anxiety and guilt. I felt responsible for the entire action. I felt deep in my heart the enormity of all 30 of us being incarcerated.
“I had a very close shave with having a total nervous breakdown.
“We were only allowed out once a day to walk in this outdoor cell and you would shout out ‘sunrise’.
“And if you heard someone else shouting out sunrise, you could quickly, in those few minutes, try to discuss what was happening to you, then you were dragged off.
“I turned up one day for exercise and I heard someone whistling The Greatest Escape, I started whistling back and it was so cheesy but in a sense I can’t tell you how deeply emotional that was.
“I was dreaming of my own great escape moment but the reality was I was staring down 15 years in prison and it was brutal.”
Back in London, in the basement of the Greenpeace UK headquarters, which had become known as the “room of doom”, Ben realised he had to come up with another way of convincing Putin to let their team go home.
The group, known as the Arctic 30, were caught in a game of political football.
At the time Putin was facing growing civil rebellion and he couldn’t look weak.
And overseas, the race to conquer the Arctic oil fields was hotting up, Putin knew he couldn’t risk a rival getting there first so was going to use the Arctic 30 as an example not to test Russian dominance in the region.
So in a bizarre turn of events, Beatles legend Sir Paul McCartney proved to be a deciding factor in saving the day.
Ben explained: “We were up against this huge monolith, the might of the Russian political and judicial system. It was Putin, and what did we have against him?
“We called up the Russian office and we said, ‘who is the most famous person in Russia that we could get to support this campaign?’, without missing a beat they said that Paul McCartney is the only person who can command media in Russia in the same way that Vladimir Putin can.
“And so it became the mission to try to get Paul McCartney.
“Holy f**king s**t, he said he’d do it. Paul McCartney is going to write to Vladimir Putin on behalf of the Arctic 30.
“And it just fucking exploded, it was everywhere in Russia.
“I think he had a really big impact because it was the only chance that we got to really tell the story of the Arctic 30, unimpeded and unedited.”
Sir Paul’s letter, which was publicised around the world, coupled with the smuggled footage of Russia’s illegal boarding of the Arctic Sunrise in international waters was enough to turn the tide.
The jailed activists saw their charges reduced from piracy to hooliganism and after just over two months behind bars, they were all freed.
Greenpeace took on Putin, but after all the drama, do they think they won?
Faiza Ouhlason, who was one of the Arctic 30 and still works for Greenpeace, believes the jury’s still out but hopes this series will shine a light on the issue.
She said: “If Greenpeace lost, it means we all have lost, but I’m quite hopeful. I hope a lot of people will look at this series, the sacrifices we have suffered.
“I’m still a climate activist because I fight for something I believe in and it’s worth it.
“I want to be able to look my son in the eyes, 20 years from now, and even if we didn’t succeed, tell him that at least I tried.”
On Thin Ice: Putin v Greenpeace starts on tomorrow, BBC Two at 9pm.