The Duke of Cambridge declared “Ray Mears eat your heart out” as he brushed up on his jungle survival skills in Belize and drank rainwater from a vine.

       William was just 18 when he was taught the essential techniques by the British Army Training Support Unit (BATSUB) in Belize at the start of his gap year in 2000.

       He was reunited with his former Sandhurst sergeant major who now runs the jungle unit, and the officer described the future king – who turns 40 this year – as having “aged gracefully”.

       The duke and duchess spent more than 90 minutes on a crash-course version of the survival techniques taught to British soldiers who spend six to eight weeks in that Belize jungle.

       Arriving at the BATSUB HQ, dubbed “The Schoolhouse”, the couple were briefed on the five main pillars of survival in the environment – cooking, animal traps, shelters, water capture and fire.

       Recommended Ukraine live updates: Russia peace talks hampered by ‘very large’ gaps Why has Russia invaded Ukraine? The conflict simply explained Sign The Independent’s petition to help the people of Ukraine

       William and Kate were shown how to boil water using a plastic bottle dangling over a fire, fashion bamboo to use as a pressure cooker and make a bamboo spear to trap and kill monkeys and birds to eat.

       Looking at a guillotine styled trap, suspended five metres in the air from a tree, William turned to the press gathered to the side of the contraption and joked: “Ah, it could trap the media,” as Kate burst into laughter.

       At the shelter section in another small part of the jungle, William demonstrated his former army training by expertly splitting a giant palm leaf down middle to be used for shelter.

       Cheered on by half a dozen soldiers and his wife, the duke declared: “It’s all coming back now,” as he carefully executed the task.

       As he lifted it on to a roof already fashioned by the squaddies, impressed Kate said: “It’s really sturdy, it’s amazing.”

       At the penultimate section, the couple were able to handle a huge water vine hacked down with a machete as William roared: “Ray Mears eat your heart out.”

       As they were helped to raise the giant vine aloft to take a drink of water William suddenly rocked back laughing, saying: “It’s got a bit of bark in it. Nothing wrong with a bit of Belizean bark.”

       Before leaving, the duke and duchess were able to learn about the close cooperation between the British Army and conservation organisations like Friends for Conservation and Development (FCD) and animal welfare charity Panthera.

       Both organisations are working to protect and promote the Chiquibul Forest, which is part of The Queen’s Commonwealth Canopy.

       The couple were handed two pictures of majestic jaguars which are part of a revolutionary tracking programme in the local jungle and were named William and Kate in their honour.

       After being reunited with William and meeting Kate for the first time, BATSUB commander Lieutenant Colonel Simon Nichols said: “It was great to see Prince William again as it always is. I was lucky enough to work with William and Harry during their time at Sandhurst.

       Recommended Andrew to attend Philip memorial in first public outing since settling sex case Ukrainian girl who sang Let It Go reunited with mother as she performs in Poland Boris Johnson is ‘desperate’ to visit Ukraine, says Oliver Dowden

       “William has aged gracefully and much the same man as I remember. I hope their time here was useful and they enjoyed themselves.

       “Every time I am in the jungle you learn a lot, every day is a school day in this environment.”