Vishal Chauhan, 30, a former A&E doctor

Vishal Chauhan had been working as an A&E doctor for nine months, but had become increasingly disillusioned. Each shift he felt as if he was facing a wave of human suffering – a seemingly endless stream of patients with chronic mental and physical health problems, many of whom had attempted suicide. They were patched up and sent back into the world to face the same underlying problems.

“I began to realise that we were just mopping up the failings of a society that does not value good health,” he says. “A society that is failing people rather than helping those who have been marginalised.”

Chauhan’s first thought was to volunteer as a medic, helping people at the refugee camps in Calais. But another doctor who had worked in public health around the world said he might do more good trying to prevent the billions of people who, according to the UN, will be forced to leave their homes in the next few decades by the escalating climate crisis.

“When you realise that behind those huge figures will be billions of individual stories of people who have been forced from their homes because of war or famine … And we do not know how this will play out,” he says. “It may be people in the UK who are forced to flee in search of food or safety, it may be people needing to come to the UK … I realised there are huge things coming towards us and I felt compelled to act.”

Alongside his work in A&E, Chauhan trained in mindfulness and meditation and initially approached Extinction Rebellion (XR) offering to run free mindfulness courses for activists on the front line. “When XR were first mentioned to me by friends, I remember thinking ‘Erm, not sure mate, all this talk of “extinction” is a bit excessive isn’t it?’”

“I was sitting in my cushty flat in Tunbridge Wells and going out for nice meals a couple of times a week and thinking: ‘Surely these people have got it twisted a bit here – they are a bit extreme, aren’t they?.’”

Still, he thought he would go along to one of the group’s meetings. “A few days later, someone got in touch and said: ‘We do not have a long-term wellbeing team – can you help?’ And that was it. I was then co-ordinator of the long-term support team.”

At first, Chauhan stayed on the periphery working as police liaison, first aid and activist support. “I was petrified of getting arrested, so I took every hi-vis jacket role i could find! I was like: ‘I am here to observe and oversee rather than actually being involved, so you can’t arrest me.’”

But slowly, as this year went on, he became central to the support team set up within XR that ensures the vast majority of those arrested have someone to meet them when they are released – and that they receive ongoing support.

Initially, he says, he was always planning to go back to medicine. But by this autumn, he realised there was no return, and now says he will continue to dedicate himself to XR full-time.

“My understanding of the crisis we are in has just dropped deeper and deeper, and as that happened it became more apparent to me that working in a hospital was not serving my purpose – of really helping people – as much as working with XR is.”

As a doctor, he says he has a duty to act if the safety of patients is compromised; and the biggest threat to the health of British people is the chaos that will ensue from climate breakdown if nothing is done. “The only thing that I can find that is commensurate with tackling the grave harm we face from this crisis is Extinction Rebellion.”

Chauhan has been arrested and has given up his “cushty flat” and instead “sofa surfs” or lives at home with his parents who have struggled to understand his decision to turn his back on his medical career. “This has not been easy and has come at a great cost to me and my family. I can no longer financially support my parents which means they may have to move out of the family home … But sometimes you have to make a stand and do what you know is right … and that is what I am doing.”

Sue Kilroe, former retired nurse

Sue Kilroe, a former nurse and public policy academic, had been looking forward to spending more time with her grandchild and volunteering at a local arts collective in Bristol when she retired.

But last summer, months before the official launch of XR, the 75-year-old began hearing from former colleagues in mental health nursing about an emerging trend among young people turning up at their clinics – climate anxiety.

“The same thing kept coming up,” she says. “Basically a fear that we are facing extinction.”

For years, Kilroe had supported mainstream environmental groups, signing petitions and writing to her MP. But as the scale of the crisis became more apparent – both through conversations with colleagues and the mounting scientific evidence of climate breakdown – she was left with an unshakable feeling that not nearly enough had been done.

“It felt like it had all come to nothing. To be honest, in light of what was happening, it felt like a terrible failure.”

So when she first heard about XR through friends in Bristol last November, she had no hesitation about signing up. “The idea that we need to disrupt corporations and governments to force them to take the necessary action really struck home with me.”

Since then, Kilroe has worked tirelessly for the group, helping set up a Rebel Elders XR group in Bristol – a troupe of retirees who dress in silver gowns during protests. Kilroe was out on the streets for five days during the October London XR protests, grabbing a few hours sleep a night in a nearby youth hostel. “Working with other explicitly older people within the organisation has been immensely pleasurable,” says Kilroe. “There is a sense that since our generation are, in part, responsible for global warming, working for change within XR feels just.”

Kilroe says that although her working life was hectic – combining mental health nursing and a career in public policy academia with a lifelong passion defending the NHS – her life is even fuller now she has taken herself out of quiet retirement. Does she regret it? “I don’t feel like there is much choice,” she says. “We are facing a very real threat of extinction and when you face that, not just in terms of what it means for our own grandchildren, but what it means for nature and all future generations

With one grandchild and another on the way, Kilroe says the hours she spends sewing costumes, organising protests and developing tactics for XR “does not feel like a sacrifice”.

“The reasons I can find the energy to do all this at my age is that I know if I slow down and face the reality of the climate crisis on my own, knowing how awful the future will be for so many young people, I would be overwhelmed by despair.”

Andrew Medhurst, former city banker

After 30 years working as a city banker, Andrew Medhurst was beginning to feel uneasy. He had just lived through a summer heatwave in the UK, the Intergovernmental Panel on Climate Change (IPCC) report warning of climate breakdown had just come out and he found himself spending his lunch hours in the City reading scientific papers about the scale of the unfolding crisis.

After reading an article in by the Guardian columnist George Monbiot last autumn, which ended with the announcement that he would be joining the first XR protest, Medhurst decided he must act.

So, on a bright sunny morning in November, the 53-year-old former trader, who had worked for HSBC and Lloyds for almost three decades, stepped out on to Waterloo Bridge to block the road.

“I remember some bloke going out by himself into the road. All the the cars were still driving past. I thought: ‘OK, here we go,’ and I followed. Within minutes, we had closed down the bridge.”

He quit his job just before Christmas, with the view to starting 2019 as a full-time activist.

“I was working in pensions,” he says. “Over timescales of 30 or 40 years. I just thought, with what I knew [about the climate emergency], it was a complete waste of time … it was almost fraudulent.”

Since quitting his job, he has become a key figure in the movement, working closely with one of the founders, Roger Hallam, standing for election in the European elections and getting arrested three times. On the last occasion, 10 police officers turned up at his home and seized computers and mobile phones as part of their pre-emptive crackdown on plans to fly drones at Heathrow – even though Medhurst insists he was not involved in that action.

Now Medhurst runs XR’s finance department. The group has seen about £2.6m in donations in the past 12 months, most of them in small contributions. Although he has “given up his job”, Medhurst says he has rarely worked harder.

“There was a time when I worked for Lloyds and we were really up against it and I would get the 5am train to the office and get back at 9pm, but apart from that, this is as hard as anything I have done. But the difference now is that this is totally in line with my values. It’s what I want to be doing with my life.”

Medhurst recognises that he is in an “extremely privileged position” and, although others in XR take voluntary living expenses of up to £400 a week, he takes nothing from the organisation.

He says his family have been very supportive – although he says his 85-year-old dad still finds it a “bit of mystery”. He doesn’t regret his decision for a second. “I am having the time of my life doing what I think is the right thing to do, not just for my children but for future generations of humans.”

Does he have any advice for others considering a move like his? “Just don’t leave it too late to do what you think is the right thing to do.”