Sarah North has always been a passionate eco-campaigner, litter picking in Highgate Woods and doing petitions to save animals in her spare time growing up.

But last year she took her commitment to a whole new level when she stopped an oil rig by jumping in the North Sea in front of it on its way to a new oil field.

Transocean, the oil rig operator from which BP was renting the rig, is looking to hit Greenpeace with an unlimited fine through the Scottish court system, and executive director John Sauven could be jailed for two years over the protest.

Sarah, a mother-of-two, hadn't planned on getting involved in the protest and had just been in the area with her dog.

"I had no idea I'd end up on the ship, but I was asked to head down south to Newcastle and jump on board the ship," said Sarah, 50, of Kingsland High Street, Dalston, who has worked at Greenpeace HQ in Canonbury for 23 years.

"I hadn't prepared for it, but I understand the issue - trying to stop a company like BP to drill go get more oil is an incredibly important thing to do in the face of a climate emergency, but it was quite spontaneous, and I also spontaneously ended up in the water - that wasn't the plan.

"We had been following the rig backwards and forwards and stopping it get to the drill site, the only way to stop it a final time was for me to be in between the drill site and the rig, and see if it was enough to stop them.

"As I was getting dressed I was thinking of my daughter. She didn't what I was doing and I didn't want to tell her because I didn't want to frighten her."

She jumped in near to the drill site.

"We radioed to their vessel that I was in the water, and instantly made them aware," she said. "It was quite frightening. You feel safe in those situations because Greenpeace are very conscious of safety, but I'm just a single mum from Hackney and it's a big thing to get into a dry suit and jump into the north sea with an oil rig and five vessels all coming towards me.

"It was a bit of a life moment, but I felt determined."

Sarah grew up in Muswell Hill, attending St James primary and Fortismere secondary school which was then called Creighton.

Although she left school early at 13, she did A-levels at Hackney College and went on to get a first class degree in environmental sciences and a masters in conservation at University College London.

Since joining Greenpeace, she's been involved in campaigns on genetically modified foods, saving the Arctic, the Edmonton incinerator and set up the NGO's investigation unit, and now she's focusing on the 2020 United Nations Climate Change Conference in Glasgow.

"When you look at the state of the world from Shrewsbury to Sydney, we are living this climate emergency, and we've lost 60 per cent of our wildlife in my lifetime," she said.

"There are predictions that millions of people will be displaced because of climate change in the next decade and we have 10 years stop the worst impact and protect he environment. You should do whatever you can within your power to make a difference and I'm lucky I work at Greenpeace and I'm privileged to be in a situation where I can put myself in a direct action situation like that and try my best.

"I've always really loved nature, and it does go back to being a little kid growing up, spending time in Highgate Woods and on the railway line. I'd go out litter picking on the woodland path and do petitions to save animals, going house to house and knocking on doors. You know what kids are like and it just didn't leave me."