Running a marathon is hard enough, but imagine doing so with a 100lb backpack. To clarify, that’s the same weight as the average household toilet or, somewhat more appealingly, Kylie Minogue.

Although the record for running a marathon with a 100lb backpack was attempted at last year’s Virgin Money London Marathon, it wasn’t completed in the allotted time of eight hours. This means, providing he can complete the 26.2 miles in his target time of 7hrs 45mins, Chris Shirley will set a brand new Guinness World Record on April 24.

Men’s Running editor Rick Pearson went to find out more from the former Royal Marine: