Delusion. That’s the crucial prerequisite for running a marathon in fancy dress, according to the ultramarathon competitor and cancer survivor Jonathan Acott, who is attempting the fastest marathon dressed in a clanking suit of armour.

So that’s what it was when I decided to run this year’s London Marathon dressed as a badger. I’ve run a marathon once before, 19 years ago. I hated the suffering. I injured myself. And now I’m 51. Why was this a good idea?

It started last year. Gazing at a piece of barren farmland that Norfolk Wildlife Trust (NWT) hope to bring back to life, I decided I would help. People taking local action to make the world a tiny bit better is a hopeful antidote to global doom-and-gloom. My nature-loving dad, who used to volunteer for NWT, died last year. With NWT celebrating its 100th birthday this year, it seemed a good moment to raise money for its efforts. The badger is the symbol of the Wildlife Trusts and I have a badger onesie in my wardrobe. And so, I began training, driven by that strange constellation of personal and idealistic notions that make people choose to embrace pain for 26.2 miles.

Running in a costume liberates me from my egotistical drive for a certain time; I just want to finish. And training started well. I plodded an 18-miler, then a 20-miler (not in costume) and then, six weeks ago: disaster. I pulled the same calf-and-tendon I’d knackered in my last marathon. Turns out it never properly healed. On medical advice, I’ve rested ever since – a ridiculously long taper.

On the plus side, the London Marathon has a new feature called Woodland Way at mile 10 – a space lined with native trees, playing calming nature sounds – where a badger will be right at home. And when I complete the race, I can choose to plant a tree with a marathon charity partner instead of receiving a finisher’s T-shirt.

But my anxiety is rising. Will I finish? Will it be unbearably hot? Why does anyone do such a difficult thing in public, in fancy dress? Are we all deluded attention-seekers?

I decided to ask my fellow fancy-dress marathon runners.

Fiona Betts, helicopter (2023 and 2026)

Top tip: don’t go out too fast, and don’t think you can bag some quick miles – it never pays dividends.

Fiona Betts got back into running when she was 47, her boys had grown up and she had a bit more time in her life. She thought it would be fun to set a fancy dress record but found it harder than she imagined. The records are strictly categorised. She fancied running as Princess Fiona from Shrek but that’s “animated film character, and they are super-fast”, she says. “I can’t run a marathon as quickly in fancy dress.”

When she saw an air ambulance land in the field behind her house in Ashby-de-la-Zouch, it sparked an idea: run as a helicopter and raise money for Air Ambulances UK, which supports all the regional services. And the “3D Aircraft” world record category was there for the taking.

Fiona set the record in 2023. “Now I want to break it,” she says. “Years and years ago, as a kid, I always loved watching the Record Breakers show.”

This year will be her 28th marathon, mostly not in what she calls her Fizcopter. “It’s gone a bit haywire,” she says of her running habit. She trains in her ’copter and is known as “the helicopter lady” around her home town. Although her costume has the benefit of not covering her head, it gets stonkingly hot inside. On a cool day recently, her sports watch informed her it was 31C inside. “I’m of an age where I run hot all of the time,” she laughs.

Betts is experienced, she knows she can do it, and London is like no other marathon, she says. “It’s just something different – the atmosphere and the acceptance of fancy dress costume. It’s the hardest thing I’ve ever done and it’s the most fun marathon.”

Jonathan Acott, suit of armour (2026)

Top tip: if you haven’t done enough training, you haven’t done enough. Deal with what’s in front of you, not shoulda-woulda-coulda.

Jonathan Acott is kind enough not to paraphrase Crocodile Dundee – “A badger? That’s not a costume. This is a costume” – when we speak. First, he trained with weights strapped to his wrists and a weight-vest to mimic the real suit of armour he will run in. Then the real suit “didn’t feel quite as awful as I thought it might”, he says.

His London marathon in armour is actually his first fancy-dress, and he’s going for the Guinness world record: 6hr 47m. “I quite like the metaphor of the armour,” he says.

I can only marvel at his pain threshold. “I’m alright with pain,” he says. “I’m constantly in a degree of discomfort, whether it’s my back or knees or just from years of chemo and surgeries.” Acott has survived six bouts of cancer, multiple operations and chemo since he was first diagnosed with testicular cancer in 2004, aged 29. Eighteen months after his most recent operation to remove one cancerous kidney and his spleen in 2018, he ran the Berlin marathon. He went on to become the first six-time cancer survivor to run a marathon on every continent. “I’m not in remission. The best I can hope for is no active cancer,” he says. “Marathons have never been about the race. They are a celebration of survivorship.”

Unsurprisingly, Acott is driven by empathy for those who have been through what he has. He’s running for The Gift of Go, a charity he founded to provide micro-gifts to patients and carers “caught up in the blast rays of cancer”, as he puts it. “Joy is a necessity. It’s an essential. And the first thing to go with cancer is joy.” His charity buys, for instance, pottery lessons for a carer if that’s a desired distraction, or trainers if they want to take up running.

Acott is now a motivational speaker. He makes a marathon in armour sound easy for him but it’s not. “I’m very happy standing up on stage. But the idea of people seeing me in armour in the London marathon is humbling, terrifying and mortifying at the same time.”

Alex Morris, polar bear (2025)

Top tip: set no expectation, apart from fun.

The experience of running the London Marathon in a plastic-lined polar bear costume is not encouraging. Alex Morris trained diligently. The polar bear came about because the property company for whom he is a quantity surveyor, Morris & Co, mounts polar bears on the roof of its Shrewsbury HQ each Christmas. So Morris thought he’d boost his fundraising by running as his home town icon. “I became the polar bear guy in Shrewsbury,” he says.

Training went so well he set a time target of 3hr 45m. Unfortunately, marathon day 2025 was hot. “My Garmin was recording 28C air temperature and that’s what really caught me out,” he says. The costume “was the hottest thing I’d ever been in. It didn’t wick away any sweat. I got to mile three and realised that was a challenge. It became mini-plan after mini-plan – get to the next water station. It was the longest day of my life. It was horrendous. Twice St John Ambulance staff had frank conversations with me – ‘Is it worth it?’ and ‘Listen to your body.’”

“There were tears,” he says. “There was a lot of fundraising [he raised more than £6,000 for Mind UK] and, internally, you don’t want to let people down. I’ve had friends struggle with mental health and the construction sector has really damning mental health statistics. Traditionally big macho builders don’t want to talk about how they feel.”

He battled on, buoyed by the “incredible” support of the crowds. “In the hardest moments, the crowd were 10 deep, cheering you on and passing you drinks. I was struck by the diversity of London – Pride Corner, reggae acts, a priest throwing holy water over the runners, children – every person from every part of society was cheering people on.”

Morris finished – 2kg lighter. He’s not running this year but he would do it all over again. “I’d love to do another one in fancy dress, but perhaps something a little bit airier. It really brings the fun. Running has been quite boring ever since.”

Jo Robinson, lobster (2024), two-person inflatable elephant (2026)

Top tip: soak up the atmosphere, enjoy it, and don’t take it too seriously.

When Jo Robinson ran as a giant lobster in the 2024 London Marathon, she was fit, prepared and gunning for the fastest crustacean world record. “I trained for it being too hot but I hadn’t trained for the rain,” she says. Her costume was a huge, mascot-style affair, and it rapidly became wet and heavy. “It was like running with a towel wrapped around my legs. I finished, but I didn’t get the record.”

This year, she’s back for more, alongside her friend Emma Langstaff. Locked together in an inflatable elephant, they are aiming for the two-people-in-an-inflatable-costume world record. Their target is five hours and I am sure they will smash it: Robinson’s personal best without a costume is an awesome 3hr 5m at London; Langstaff is just as quick. “On paper it doesn’t sound too bad, but then we put the elephant on. To start with, we could only run 14-minute miles – we’re not going to break a record at that pace,” says Robinson.

Now they’ve sorted out their rhythm and sound well set, even though Robinson says they haven’t trained much in costume. “We’re just going to see how it goes on the day,” she says. (Which is exactly my overly hopeful approach.)

Like most runners, Robinson has a deeply personal drive to run. Both her daughters have type 1 diabetes and she has witnessed the relentlessness of this invisible condition, which demands up to 300 daily decisions about insulin, food and activity. Her chosen charity, Breakthrough T1D, campaign for better treatments and technologies for everyone with type 1.

When Robinson, who now owns a beach cafe in Cornwall, used to live in London, she never knew her neighbours. On marathon day, however, “all normal rules are broken” she says – strangers chat and cheer on strangers. “It’s a really special day. The world’s a pretty crappy place at the moment. If we can all go out and support each other, that’s a great thing. The London Marathon just brings out the best in people.”

Toby Freeman, a pair of testicles (2025 and 2026)

Top tip: take stock of what you’re actually doing – how bonkers it is – and enjoy the moment.

Why do you run marathons as a big pair of bollocks? It’s not a journalistic question I ever expected to ask. But Toby Freeman has an excellent reason for doing so. He lost his older brother, Rob, to testicular cancer aged 24. Freeman quit his job to be with him at the end. Fourteen years ago, he founded the Robin Cancer Trust, vowing to raise awareness and cast aside stigma.

Freeman found a specialist costume-maker who devised a truly standout costume: a pair of giant testicles, which make him 7ft tall and 3.5ft wide.

“We know each other intimately now,” he says, after running Brighton, London, three back-to-back ultramarathons and a load of lesser races as “the Big Ballsy Runner”.

Last year, London’s searing heat was tolerable because his legs and arms were free, and he could be splashed with water. “Rain is fine too, but the wind! It was windy in Brighton and it was so hard. I was literally stopped in my tracks going downhill by the wind.”

This year, he was aiming to break the “body part” world record of 3hr 32m. He trained for seven months for that time, only to discover it has recently been smashed and is now an unreachable 3hr 14m. “I just don’t have that in my legs,” he says.

He is relieved not to be going for a record and his race-day attitude is something I can only hope to emulate. “The longer I’m out there running, the longer I can interact with the crowd and thank them for turning out, and enjoy the day,” he says. “London is genuinely overwhelming.”

I assume he is a massive extrovert but Freeman insists he would much rather sit on the sofa alone reading a comic. When he first ran in the costume, “I couldn’t think of anything more embarrassing. I’ve never wanted to be the centre of attention and being so takes a lot out of me – my dips afterwards are quite big. I’m physically tired but I’m so emotionally tired, too.”

Nevertheless, the experience is “incredible” and he’s raised £30,000 this past year. “If just one person gets checked out, it makes it all worthwhile.”