Watching a rhino being dehorned was both the highlight and low point of former Royal Marine Thomas ‘Sully’ O’Sullivan’s deployment to Africa as a volunteer with Veterans for Wildlife.

Dehorning, in which a rhino’s horn is humanely removed to make it a less attractive target for poachers, is a tactic employed in the fight to preserve the iconic species.

“A rhino should have a horn,” Sully said. “It’s like shaving off a lion’s mane – it is one of its defining characteristics, but if we hadn’t done it they would have been poached in a short time.”

Sully, 32, from Poole, Dorset, spent five weeks at Thula Thula Game Reserve in South Africa’s KwaZulu-Natal province. He used his experience gained in three tours in Iraq and two in Afghanistan to train anti-poaching unit rangers in basic military tactics to better equip them to take on heavily armed poachers.

“It’s not just the animals I wanted to protect; I wanted to protect the rangers and help them do their job,” Sully said.

“My deployment helped me grow as a person. The anti-poaching rangers have it a lot worse than what I thought. Seeing the dire straights that wildlife is in brought home to me that we need to do a lot more. Charities like V4W are pushing it and doing it.”