Against 300 male and female competitors of all ages, Year 12 Justine and her team mate Amelya beat every other team to the finish line completing the challenge in just 45 minutes.
The event offers a rare opportunity for civilians to try out one of the four world-famous Royal Marines’ Commando tests, which training recruits need to pass in order to earn their coveted Green Berets.
The 10km-course on Woodbury Common in Devon included all the obstacles potential Royal Marines face, from freezing wading pools to mud soaked pipes.
Justine said: “The obstacles were very challenging. The hardest was probably the sheep dip – a 3m long and narrow tube submerged completely under water and we had to hold our breath and swim through it!”
Funds raised at the event will benefit the Royal Marines Charity and Devon Air Ambulance Trust.
There is no let-up of the pace for the 16-year-old who is currently undertaking a once-in-a-lifetime expedition across the Three Passes Trek to Everest Base Camp.
Having flown into Nepal earlier this week, today she has reached the first pass at 17,000 feet. Alongside her guide, she will then tackle the next pass at 17,400 feet and descend down a 37km glacier before making the arduous climb to Everest Base Camp.
Named the Lord Lieutenant’s Army Cadet of 2018, Justine continues to go from strength to strength in the Army Cadets Force as she drives towards her ultimate goal of training at Sandhurst to work in military intelligence.