Competitors will shoot in the NFU-sponsored marquee, run along the River Thames, swim at Windsor Leisure Centre and ride a jumping course in the Frogmore Arena.
Martin, 15, will be the only boy competing for Scotland at this prestigious event on May 12 and 13 and will take part in the parade in the castle arena. There will be several additional events this year as part of the Queen’s Diamond Jubilee celebrations.
Martin sai: “I’m thrilled. It’s a huge privilege to have been selected in this special year.”
Martin, a fourth year pupil at Earlston High School, has been training hard.
Callum Crawford of the Duke of Buccleuch Pony Club has been helping him with his shooting and running.Martin trains regularly with Duns Amateur Swimming Club, coached by Alison Affleck.
Martin will be riding a 17hh thoroughbred horse, Nostromo (Spider), at Windsor. Spider is owned by Amelia Jobling of East Sussex.