On Thursday night, Cliff Harris, a man growing increasingly accustomed to bizarre and frightening occurrences, was sitting at home in Devon watching his daughter Alex tell the 10 o'clock news how she used a radiator pipe, a spoon and an alphabet code to communicate with her friends and keep herself going in a freezing Murmansk jail.

It was not, he says with a degree of bemused understatement, something he ever expected to see. But then again, there is not much about the past nine weeks that either the 63-year-old agronomist or his 27-year-old daughter could have predicted in a trip that saw a "real Devon country girl" turned into the public face of Greenpeace's Arctic 30 campaign.

When the family said goodbye to Harris in Norway in early September, all they were expecting was for the Greenpeace digital communications officer to have a little adventure and see the beauty of the Arctic for herself. "They were just going to highlight the dangers of oil drilling in the Arctic," her father told the Guardian. "It was quite a shock when we saw the footage of the Russians boarding the ship."

Just before she left, she had sent an email to Becky Mercer and some of her other university friends. "It's possible that we could be arrested," it said. "But it's a pretty low possibility. If you hear protesters have been arrested, that's not me. But if you hear that the crew have been arrested, then panic. LOL."

But news of her arrest in mid-September and the Russian authorities' subsequent decision to charge the 28 activists and two freelance journalists with piracy, and then with hooliganism, did not prompt much laughter.

According to her father, although Harris cares deeply about the environment, she could hardly be described as a direct activist. "When she was a young child, if ever there was a documentary or any news items about animals losing their habitat or facing extinction, she would watch it and you could see she was concerned about what she was hearing and seeing," he said.

Graduating with a marketing degree from Bournemouth university, Harris worked in Abu Dhabi for a year before taking a few months off to travel. On a visit to the Amazon she saw what oil spillages could do to an ecosystem. She has lived in Australia for the past four years and worked for Greenpeace for the last two.

Despite the fact that six Britons – including video journalist Kieron Bryan – remain in St Petersburg on bail, much of the attention has focused on Harris. In a letter her parents shared with the Guardian in October she detailed her struggle to deal with life in an Arctic jail. "Being in prison is like slowly dying," she wrote, in a letter that put her at the heart of the campaign to free those held. "You literally wish your life away and mark off the days."

Appearing in court for appeals first in Murmansk, and then St Petersburg, the Greenpeace activists could be divided into two groups: those who put a brave face on it – and in some cases even seemed to believe that if their incarceration was raising awareness about Arctic drilling, it was perhaps even worth it – and those who looked completely shocked and overwhelmed by the experience.

Harris fitted into the latter category. During her first hearing in Murmansk, her voice was choked with emotion as she recalled how she had asked for doctors to attend to her stomach pains but been ignored. At the second hearing, the stern judge who had been doing a passable impression of Anne Robinson for much of the hearing appeared visibly troubled by Harris's emotional plea to be set free.She told the translator to tell Harris to "be calm", and asked if she would like a break in proceedings to compose herself.

But those who know Harris insist the appearances do not quite give the full measure of her. Ben Stewart, who is co-ordinating Greenpeace's campaign to get the Arctic 30 home, said: "She said she never realised herself how strong she was and she had got a lot – in her words – 'stronger and wiser' in jail because of the level of adversity that she was facing."

Kieron Bryan, who met Harris for the first time as they boarded the Arctic Sunrise only to discover that they had grown up a few miles from each other in North Devon, says she was obviously delighted to be part of the Greenpeace campaign. "I saw a picture of her in court looking so upset and that was really moving and really hard to take," he says, "but I kind of expected her to stay strong."

Bryan knows that the Arctic 30 episode raises questions about the dangers of protesting in Russia. Although there are serious discussions to be had when everyone is safely home, he believes no one could have predicted the overwhelming scale of the Russian response. "I wouldn't have joined the ship if I didn't feel safe with the organisation because they're an internationally recognised environmental group," he says. "This is not some fly-by-night organisation who haven't done these things before," he says.

Stewart says Greenpeace is satisfied that it carried out the correct risk assessments based on the evidence it had but stresses that the group is going to hold "a really, really thorough debrief" when it's all over, adding: "It would be utterly negligent if we didn't."

For as long as the Arctic 30 remain on bail in Russia, though, Alex Harris seems destined to remain the enduring face of a situation she had previously only dared joke about. "She's not one of those people that wants to be the centre of attention," says Becky Mercer. "But if it keeps their plight and the plight of the Arctic in the press, I think she would be happy to do it."