ITV News Correspondent Paul Davies reports
Running the equivalent of 100 marathons sounds like a feat, and then when you factor in that it's all being done in bare feet, it becomes even more of one.
Anna McNuff is the athlete behind the challenge and she's doing it all to inspire girls to be more adventurous.
McNuff is an ambassador for Girlguiding UK and will be dropping into units across (or all the way down) the country to talk to "them about adventures and the outdoors, and I’m showing them that adventures are for girls as well,” she told ITV News.
Running barefoot the length and breadth of the British Isles is not without its obvious challenges though.
“The kinds of things you step in as you go along, and I’m talking everything from all the different kimds if poop, to dead animals.
"I’ve stepped on a dead rabbit,” she recalled.
However, Ms McNuff says the most difficult times have been navigating through cities.
“Coming into cities, the glass and the grit - that’s the tough stuff and those are the times when I think, what am I doing?” she said.
Ms McNuff is 1,000 miles into her barefoot journey, beginning her adventure in the Shetland Islands in June, and aiming to end it in London in November.