It was the image that triggered a global debate about motherhood. A little under halfway through one of the world’s most gruelling races, the 105-mile Ultra-Trail du Mont Blanc (UTMB), Sophie Power, 36, was photographed at an aid station near the Italian ski resort of Courmayeur breastfeeding her three-month-old son, Cormac.

Within days, the image had gone viral and was picked up by newspapers from India to Indianapolis.

Now back at home in Islington, north London, giving her first interview to a newspaper, Power, who until last week did not even have an Instagram account, said she had been ill-prepared for the attention she was to receive on social media, but was pleased about the conversation she had started.

“It has highlighted something that women feel really unable to talk about. There is this huge mother’s guilt that all the time you need to be 100% focused on your baby, and I’m saying that by not focusing on your own physical and mental health you can’t be the best mother. For me, personally, I need to be physically fit and have those mental breaks. Women really struggle to be open about saying that.”

Sophie Power: ‘We shouldn’t have to lose who we were before we were mothers. Men certainly don’t.’ Photograph: Alexis Berg/AFP/Getty

She said she had thought little of the photograph when it was taken. “In the picture, I’m just focused on feeding Cormac, pumping the milk. Probably a metre out of shot is my husband, John, trying to convince me to eat an avocado sandwich and going through my pack, changing over my head torch batteries, putting the food in there. Alexis [Berg, a photographer with the online running community Strava] asked if he could take the photo and we thought nothing of it. We thought it might make a small Strava story about women doing something a bit different during the race.”

Considering she has run almost 50 miles, Power, co-founder of a company that tackles inner-city air pollution, seems relatively composed in the picture – especially compared with the exhausted male runner lying flat out on his back next to her.

“I’d gone through the first night with no sleep, as a lot of runners had. But as a mother I was really prepared for that. In terms of sleep deprivation, I was probably the best trained person on the start line. I’d had 20 minutes’ sleep over two nights. But I was taking the race really gently. Some people racing UTMB were pushing themselves to the limit. I had to do the opposite. I was trying to keep a lot of food down for my milk supply. I was almost refreshed when I got there compared to a normal race.”

Before the UTMB, which she finished in just under 44 hours, Power had run several of the world’s most famous ultra races including the Marathon des Sables across the Sahara and the 153-mile, non-stop Spartathlon in Greece.

“I started running in 2009 pretty much from scratch. I’d never run more than a mile in my life when I signed up for the Marathon des Sables not really knowing what it was. I signed up to an ironman barely able to swim a length of a pool.”

To enter the UTMB, she needed to earn points by running other ultras. Power had a place in the 2015 UTMB but had to give it up because she was six months’ pregnant with her first son, Donnacha, now three.

In contrast with injured athletes, the UTMB does not allow women to defer their places if they become pregnant. In 2018, having bagged another place, Power faced a dilemma: run or spend years amassing more points.

“This would mean missing out. I never set out saying I had to finish the course. I just wanted to be in nature, to see how it goes.”

It was the thought of running the final metres through Chamonix with Donnacha that had kept her going through the race’s toughest stages. “I had to tell him to slow down, he was too fast, my legs were too tired. I picked up Cormac about 50 metres from the finish and crossed the line with both of them.”

While the photograph has been well received on social media, there has been a backlash. A Twitter poll by a runner’s magazine asking if readers thought Power’s actions were “gross, a little selfish” or “it’s her business” was taken down after readers complained.

Overall, though, Power feels her 15 minutes of fame have sent out a strong and unambiguous message.

“This picture has allowed women to say: ‘When we become mothers our self-identity doesn’t change.’ We shouldn’t have to lose who we were before we were mothers. Men certainly don’t. You see all these great pictures of dads crossing finishing lines with their babies. Why do we as a society see that as different for the mother?”