For the past few weeks, I’ve been getting ready for Christmas. As well as putting the tree up ridiculously early, I’ve made the cake, bought the presents and assembled the stockings. Even though my children no longer believe in Santa, the crinkle of my dad’s old golf socks stuffed full of presents on Christmas morning still makes their faces light up.

But this year, for the first time since they were born, I won’t be there to celebrate with them. I’m leaving my husband Fred, daughter Inès, 15, and son Vincent, 12, to row 3,000 miles across the Atlantic as part of the annual Talisker Whisky Atlantic Challenge. My four-woman crew of mothers is called the Mothership, and between us we have 11 children, the youngest of whom is four.

At the end of November, I flew out to La Gomera in the Canaries for two final weeks of preparation before we set off on 12 December. Walking out of the house at 5.30am knowing I wouldn’t see my children again for at least two months was the hardest moment of all. If it goes according to plan, the next time I see them will be on the shore at English Harbour in Antigua at the end of January. The longest we’ve ever been apart is two weeks.

My husband has been fully supportive, in the same way that he put up with me doing endless marathons in my 40s. He’s the main cook at home as well as the stricter parent, so I have no qualms about leaving him in charge of the household for several weeks. Finally getting around to writing our will was an unsettling moment – there’s nothing like confronting your own mortality.

It’s been harder with my kids, who have put my decision to take part in the race down to a midlife crisis. While my crewmates have been dealing with tears from their kids, I’ve had to put up with sarcasm. “I couldn’t care less what you do,” my son told me during a last meal out together. I’ve been troubled by the thought that in order to deal with me going away, they’ve started to withdraw from me. Their brave faces are even more gut-wrenching than tears would be.

It’s not only family who are worried. I’ve been immensely moved by the love and affection I’ve had from friends in recent weeks. They’re excited for me, but there’s another undercurrent of feeling that only the most outspoken express: what if I don’t come back? The first box you have to tick when you sign up for TWAC is the one which says, “I accept that ocean rowing is a dangerous sport.” It’s less dangerous than it used to be – the boat that race founder Chay Blyth first rowed across the Atlantic in 1966 was fully open to the elements – but there are many risks involved.

Mrs Nelson, the sturdy 28ft boat that will be our home for at least 40 days, is designed to roll and pop back up if we capsize. My worst fear is that it won’t, and we’ll be upside down in our tiny cabin in the middle of a storm. Everyone imagines we have a safety yacht behind us at all times, but although there are two, there are 36 boats in the race fleet. We’ll probably only see them once, and for most of those 3,000 miles we’ll be bobbing around on our own. In an emergency, we’d have to summon the nearest ship.

At 3am, the enormity of all the unknowns we are about to experience can be overwhelming. So what has motivated me to take on this extraordinary challenge, one that only 226 women in the world have ever completed? Is it just a midlife crisis, or something deeper?

The straightforward answer is that the opportunity came around by chance and I felt I would regret it forever if I turned it down. The Mothership had a late drop out at the end of June, and my friend Jo, who I’d rowed with at Oxford University, felt I would be a great fit for the crew.

But there’s more to it than that. Three years ago, I was made redundant from my job as a magazine editor. One day I was looking after 40 staff and two magazines, and the next I was waking up at home with a terrible gin hangover wondering what I was going to do for the rest of my life.

I floundered for a while, but then life began to slot into place again. In June 2019, I went (as a beginner) to a paddleboarding competition in Lake Annecy in France. Having not rowed competitively for 24 years, I rediscovered both the joy of being on the water and the thrill of racing.

There, I met Debra Searle, who famously did the Atlantic challenge alone in 2001 when her then-husband had to be rescued from their boat, suffering from anxiety. I listened to her tales of life at sea, little imagining I would be doing the same just two years later. The trip inspired me to take up rowing again, at the Lea Rowing Club in Hackney. Although the two seasons I’ve done have been dogged by shutdowns due to the pandemic, training to compete this summer at Henley Masters ensured I was fit enough to join the ocean rowing crew at the last minute.

In the past couple of years, I’ve also interviewed Kelda Wood, the first disabled woman to row the Atlantic solo. She was unsparing in her description of how hard it was and how much she’d hated being alone, yet she was so fulfilled by what she’d achieved. Then I chatted to Pip Hare, who sailed around the world solo in the Vendée Globe. Like Debra, they were both amazing, tough women whose words inspired me and made me wonder what I could be capable of.

And now, here I am, about to set off for the world’s toughest row. I’m facing 40-50 days at sea, rowing two hours on/two hours off continuously. We won’t sleep for more than 90 minutes at any one time because in our off shifts we also have to fit in eating, going to the loo (in a bucket), and washing the salt off our bodies. Blisters and sores will develop rapidly if you don’t.

Pain will be constant. I already know from our long practice rows around the Solent that the last 15 minutes of any two-hour shift can be teeth-clenchingly agonising. It took my hands days to recover from a 72-hour row, so I have no idea what state they will be in after six weeks. There will be little we can do for aches and pains bar taking some ibuprofen and soldiering on. Rowers are most likely to be removed from the boat with sea sickness, which develops once you lose sight of land. Some can’t adjust and the constant nausea becomes too debilitating.

Everyone who has completed the crossing will tell you that it’s 80% in the mind, but beforehand contestants tend to focus purely on the physical. We’ve been doing two-hour sessions on the rowing machine, weight-training and endless pilates. The cabins are awkward to climb into at the best of times, let alone when the boat is crashing up and down 30ft waves, so flexibility is key.

Building resilience is even more important. I’ve thought a lot about those early days of motherhood, when I went through 17 hours of labour, then days of sleeplessness, coupled with the huge emotional burden of having to keep a small human alive. That is one of the strengths of the Mothership: as mums, we have to be tough, resilient, and excellent multi-taskers.

This isn’t simply a personal journey of recovery. My wider aim is to show that being a mother doesn’t mean being subsumed by your children. It’s not selfish to want to push yourself and experience extraordinary things, and I hope it will inspire women and girls to believe that adventures aren’t reserved solely for men.

I also love the sense of satisfaction I get from raising money by putting myself through intense pain – it’s a peculiarly British trait. We’re lucky enough to have secured a sponsor in the shape of Tritax Big Box, a real estate investment company, so every penny we raise goes to our charities, Women in Sport, the Felix Fund and the Noah’s Ark Children’s Hospice. Out there on the ocean, when times are really tough, it will help to know we are not just doing this for ourselves, but for others as well.

It is heartbreaking that I’ll be missing this precious time with my children – there aren’t that many Christmas Days left before my daughter turns 18. Instead I’ll have to put up with one crackly phone call, as I open the present they’ve hidden in my luggage. I will miss them terribly, and they will miss me. But I know they are secretly proud of me and that makes it all worthwhile.

justgiving.com/team/themothership