More than a month after Russian coastguards seized 28 Greenpeace activists and two journalists in Arctic waters following their attempt to board a Russian oil rig, it is no wonder John Sauven is looking exhausted.

The organisation’s UK executive director has worked every weekend since the incident in the Pechora Sea while leading efforts to secure their release, but is still finding it difficult to sleep.

He is in a constant rush – our interview, which was brought forward a couple of hours at the last minute so Mr Sauven could attend a hastily arranged meeting at the Foreign Office, was mostly held in a taxi. Yet he is at pains to point out that his stress and fatigue pale in comparison with the problems the Arctic 30 and their families face.

“Russia is sending out a clear signal, saying ‘hands off our part of the Arctic and hands off complaining about our right to drill for oil there’. It has certainly sent a very loud and very clear signal about that to Greenpeace, there is no question about that,” the 59-year-old tells The Independent.

The Russian authorities have charged the party – made up of 19 nationalities, including 6 UK nationals – with piracy and refused to bail any of them. Many have been kept in cold cells and solitary confinement.

In the 23 years he has worked at Greenpeace, running its UK office since 2008, Mr Sauven has never seen so much backing – citing support from German chancellor Angela Merkel, who called Mr Putin to warn him of her concerns, as well as the former US Secretary of State Hillary Clinton, and Brazilian President Dilma Rousseff.

“It’s been quite extraordinary actually, the support that’s been there for Greenpeace,” says Mr Sauven. “If you look at the peaceful protests that have been happening around the world, they’ve happened in every continent in every major city. About 1.5 million people have written letters to ambassadors, and we’ve had a huge number of people come out and raise the issue,” he says.

“Many celebrities – and behind the scenes, many, many more people – have privately written to President Putin or have raised their concerns in different ways. People have connected to us in unprecedented numbers.”

However, the recent case of Pussy Riot – in which two women were sent to jail for two years after being convicted of hooliganism after they performed a song critical of President Putin in a Moscow Cathedral – suggests the country pays little attention to foreign outrage.

While critics of the Russian government say there should be little surprise at their actions, Mr Sauven points out that Greenpeace has been campaigning in the country for more than 30 years, on issues such as whaling and nuclear testing, and has never faced anything like this.

“They have seized our ship and incarcerated 30 people, which isn’t something you do lightly – and it is very different to the way that they’ve reacted to us in the past.”

To a degree, Russia’s zero-tolerance message is getting through – it is unlikely that Greenpeace, or anybody else, will attempt to scale a Russian oil rig in the foreseeable future. But the case has also backfired against Russia, increasing awareness of the country’s Arctic oil drilling campaign as well as Greenpeace’s determination to curb it. Horrendous though the experience is for the Arctic 30, their families and Greenpeace, Mr Sauven says the episode has built support for its campaign against Arctic drilling.

“People around the world are now far more aware about the Arctic,” says Mr Sauven. “This is a very good thing in terms of raising awareness and building support. Where it hasn’t worked is in Russia itself.”

He claims that half of the world’s oil spills occur in Russia – estimating that Russia spills 30 million barrels of oil a year, about six times the 4.9 million barrels thought to have been spilled in the Gulf of Mexico disaster in 2010. He says Greenpeace may build a renewed campaign around that.

“They’ve got all these pipelines that are busting, you’ve got oil pouring into rivers and it’s having a huge impact on indigenous people and their way of life,” he says. “Given that Russia has the largest coastline, we really need to have the Russian people connecting to the campaign in much larger numbers than they are at the moment.”

While this probably won’t involve more attempts to board rigs, there are other ideas. “We need a more creative way to get our story across – it’s difficult to do in a country with a heavily controlled state media,” he says. “I don’t know how we would do it – maybe by going back to the old days by having a mobile cinema, or taking out paid adverts, or using social media to connect to people. And maybe investing more in terms of being able to do it.”

Mr Sauven joined Greenpeace on a temporary basis in 1991 while waiting for a place at teacher training college and has never left. The father of two is a former editor of CND magazine and has the manner and appearance of an English professor, although he studied economics at Cardiff University.

He is a veteran of campaigns like this one, which seeks to galvanise opposition by highlighting the huge damage to the pristine Arctic environment that would result from any oil spill, which the tough weather conditions would make especially difficult to tackle.

And all this comes at a time when research shows that two thirds of the world’s proven fossil fuel reserves need to stay in the ground if we are to have a decent chance of limiting global warming to the official 2C target – beyond which the consequences becoming increasingly devastating.

Whatever happens to the Arctic, it looks likely that the case against the 30 protesters could drag on for a while – and given Russia’s track record in these matters, there can be no guarantee that justice or reason will prevail.

Disturbing stuff: Greenpeace stunts

Famous for disrupting numerous Japanese whaling fleets over the years, its eye-catching stunts are rarely out of the headlines. In 2008, Greenpeace protesters breached security at Heathrow airport, climbed on top of a British Airways jet and unfurled a banner protesting against a third runway.

In 2011, at the Coppa Italia final, activists scaled the Stadio Olimpico in Rome to suspend a huge yellow banner from the roof of the stadium demonstrating against nuclear energy in Italy. With authorities unable to react until the game had ended, the message was seen by the game’s global television audience for more than an hour.