Roger Allsopp, a 70-year-old grandfather and a retired breast cancer surgeon from Guersney, completed the 21-nautical mile swim across the English Channel in 17 hours and 51 minutes - setting the new world record for for the Oldest person to swim the English Channel.
The Guinness world record for the Oldest person to swim the English Channel (female) was set by Linda Ashmore (UK, b. 21 October 1946) who crossed from England to France in 15 hr 11 min aged 60 years 302 days.
Guinness World Records also recognized the world record for the fastest crossing of the English Channel by paddleboard: 5 hr 9 min by Michael O'Shaughnessy (USA).
Roger Allsopp waded into the chilly sea at Shakespeare Beach in Dover, southeast England, aiming for Cap Gris-Nez on the northeast French coast, some 21 miles (34 kilometres) away.
Roger, who is 70 years and 115 days old, said: "I do feel an immense sense of achievement and relief that I have been successful. This has been an incredible personal challenge for me and my focus has always been to help raise money for Hope for Guernsey and Wessex Medical Research, a cause that I am extremely passionate about.
"Coupled with the fact that a man of my 'grand' age can achieve such a physical and mental challenge proves that you can live younger if you keep active in mind and body.
The retired breast cancer surgeon, from the Channel Island of Guernsey, was accompanied by a support boat to help him navigate across one of the world's busiest shipping lanes.
Mr Allsopp has been raising money to fund world-class medical equipment to help advance cancer research at the University of Southampton.
The money would pay for new equipment to analyse the blood of cancer patients and non-cancer patients to develop a test that would give a pre-warning of cancer.
"This record-breaking swim will hopefully raise a large proportion of the £750,000 that is needed to fund cancer research. The great thing about this money is that it will all go direct to purchasing this technology."
At 70 years and four months, he beat the current world record holder, George Brunstad, the uncle of Hollywood star Matt Damon.
Retired American Airlines captain Mr Brunstad, from Connecticut, swam the Channel at 70 years and four days in 15 hours and 59 minutes on August 29 2004.