Keith Digby, 54, first took the plunge after reading of the health benefits of cold water immersion, including staving off depression and dementia.
Keith’s mum Jan, 77, has lived with dementia since her mid 60s and has been in a care home in Arlesey for the past four years. She no longer recognises her son and Keith could not see his mum at Christmas because of tier 4 restrictions.
He said: “I have seen the devastating effects of dementia first hand with my dear mum suffering daily. I did get to visit a couple of times in November and the start of December for 15 minutes in an outbuilding with heating and a plastic screen, but she just fell asleep both times after a couple of minutes.
“The home’s carers are fantastic and my daughter Meg works there part-time. They sent me a lovely photo on Christmas Day.
“Each day in December, I have spent a minimum of 10 minutes submerged in our fishpond in just my boxer shorts, come rain, shine, wind, ice or snow.”
As his charity efforts took off, friends, family members and fellow firefighters started joining him in the water, alongside about 30 fish.
Keith’s wife Sian, a nurse, wrote a touching poem to highlight the effects dementia has on sufferers and their families.
She wrote: “You may feel anxiety and not know why.
“At the drop of a hat, you’ll break down and cry.
‘Your face is familiar but I don’t know your name.
“I once had a son who looked just the same.’ ”
On Christmas Day, Keith and Sian celebrated by having a double dip, swimming in a nearby river in the morning and then submerging themselves in the pond in the afternoon
Some of Keith’s dips have even had to take place at night after a long shift at work in Borehamwood.
To donate to Dementia UK, visit https://uk.gofundme.com/f/daily-december-10-minute-dip-in-the-pond