128 scuba divers braved the freezing winter temperatures on the 10 January 2009, to attempt to break the world record, currently held by the Australians, for the most number of divers ironing at the same time underwater.
They each had to iron one item of linen within a 10-minute time limit - and 86 of them completed the task under the watchful eye of adjudicators.
The group beat the previous world record of 72 set in Melbourne, Australia, last year. Their incredible feat at the National Diving and Activity Centre in Chepstow, Wales, was captured on camera by 11 photographers armed with special underwater cameras.
Organiser Gareth Lock said the charity challenge is set to raise £10,000 for the Royal National Lifeboat Institution (RNLI) - while raising awareness about the "joys" of underwater ironing.
Mr Lock, 37, said: "This was an unusual attempt, I admit, but it seemed like the perfect way for a load of divers to raise money for the RNLI. We advertised the event by word of mouth and via diving websites, and expected there to be quite a good turnout. But we were shocked when so many people arrived, ready and willing to take part - and even more stunned when we snatched the record."
Around 140 people from across the UK volunteered their time, with 128 of them qualified divers. Depending on experience, each sunk to the quarry bed at different depths with an ironing board, iron and an item of linen.
A record 86 divers managed the task simultaneously, while the remainder were either disqualified for starting too early, or penalised for overshooting the 10-minute time limit.