Haverfordwest dad to run London Marathon in tribute to baby son
Martin Langdon will take on the world‑famous 26.2‑mile challenge to honour his baby Tommy, who tragically passed away in 2023 after a catastrophic seizure
Last updated 26th Feb 2026
A father of four from Haverfordwest is preparing to run the London Marathon in memory of his 13‑month‑old son, who died following complications from hydrocephalus - a complex brain condition.
40‑year‑old Martin Langdon will take on the world‑famous 26.2‑mile challenge to honour his baby boy Tommy, who tragically passed away in August 2023 after a catastrophic seizure.
Martin is raising funds for Harry’s Hydrocephalus Awareness Trust (Harry’s HAT) to help support other families and increase awareness of the condition.
“He just closed his eyes and that was it.”
Born prematurely in July 2022, Tommy suffered a brain bleed shortly after birth, leading to a diagnosis of hydrocephalus. He underwent his first brain surgery at just two weeks old.
Hydrocephalus is caused by an abnormal build‑up of cerebrospinal fluid (CSF) in the brain, leading to pressure that can cause permanent damage if left untreated.
Around 1 in 770 babies in the UK are affected and it is the most common reason for brain surgery in children, yet public awareness remains low. While there is no cure, the condition is commonly managed using a shunt - an implanted device that drains excess fluid from the brain to another part of the body.
“Hydrocephalus is not one of those things you hear about, until you hear about it because it’s in your life,” Martin said. “We found out about Harry's HAT when we were in Cardiff Hospital - the neurosurgical team gave us all the information, so we got in touch and became part of a WhatsApp group initially.”
Throughout his life, Tommy went through 10 brain surgeries, battling complications including meningitis and repeated shunt infections. Tommy tragically went through a seizure, just weeks after his first birthday, that ended his life.
“Tommy had a catastrophic seizure not long after having surgery,” Martin said. “He had a seizure in the car on the way home from hospital. He just closed his eyes and that was it. My wife was driving the car at the time, and she was on her own with him. She said he was restless and she thought he had gone to sleep, just like any baby does, but obviously he hadn't.”
Running as therapy:
Martin says the support from Harry’s HAT has been “life‑changing,” and taking on the marathon helps him channel his grief into something positive.
“I just dive in; it’s probably another version of therapy without knowing about it to be honest. And because we live in such a small community - people know us and the support is always there.”
Campaigning for earlier diagnosis:
Alongside providing emotional support to families whose children receive a diagnosis of hydrocephalus, Harry’s HAT also campaigns for earlier diagnosis in babies through its Get‑A‑Head initiative.
An unusually large or rapidly growing head in a baby under 12 months old can be an early warning sign of hydrocephalus. The charity is calling for a review of current UK medical guidelines to ensure babies receive enough routine head circumference measurements during their first year - something that could help identify problems sooner.
Caroline Coates, Co-Founder and CEO of Harry’s HAT said: “We can’t thank Martin enough for his support. We know how much this cause means to the whole Langdon family and we’re in awe of their courage and determination in such challenging circumstances.
“In running the London Marathon for Harry’s HAT, Martin is shining a spotlight on this condition for the world to see. Hydrocephalus affects the same number of people as Down’s Syndrome, but it sadly does not have the same mainstream awareness. We’re passionate about changing that, and in doing so, ensuring that babies get the early diagnosis and support they deserve.”
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