King Charles III visits troops on Salisbury Plain

Charles watched as they were put through their paces learning trench warfare – famously used by First World War troops – which has become a factor of the conflict in Ukraine.

At an undisclosed location in Wiltshire, the King looked on intently as the men – many civilians who have no experience of the military – stormed a trench a few hundred metres away as the mock gun battle raged.

He told one of their senior officers when he first arrived: “You are amazing, I don’t know how you do it. I am full of admiration.”

The recruits were part of a group of 200 men about to begin week four of their training under the command of Major Tony Harris, from New Zealand’s armed forces, who talked the King through the operation.

Speaking afterwards about his chat with Charles, he said: “We were talking about the fact they’ve returned to trench warfare and the contrast with World War One and how we’re back in trenches in the 21st century.

“Because of the really stout defence the Ukrainians have put in – they’ve been able to hold Russian forces to pretty much a stalemate in large parts of the theatre – the large part of holding the line is digging in and preparing for the worst.

“We’ve always dug fortification as defensive measures. Artillery fire hasn’t changed, with shells falling from the sky you still need something to protect you and it just makes sense that this is where we’ve got to in this war.”

As the first anniversary of the conflict between Russia and Ukraine approaches, hundreds of men are undergoing the five weeks of basic training to prepare them for combat or enhance the skills of others who have already been fighting on the front line.

They are trained to survive in a hostile environment and are taught skills such as basic fieldcraft and medical care and also marksmanship and weapon handling, but the training has been adapted to reflect what is needed on the ground, like trench warfare.

Ukrainians have been trained in the UK since last summer and during the past six months 10,000 troops have left combat ready, with a further 20,000 expected to go through the five-week course in 2023.

Charles met Volodymyr Zelensky earlier this month when the Ukrainian president flew to the UK for talks with Prime Minister Rishi Sunak.

Downing Street announced at the time that the Ministry of Defence (MoD) would train Ukrainian pilots on Nato-standard aircraft, but the UK has yet to commit to providing RAF aircraft to Ukraine, with the Prime Minister only saying he has not ruled it out.

The first anniversary of Russia’s invasion of Ukraine falls on Friday, with Ukraine’s defence minister Oleksii Reznikov expecting a major Russian offensive to mark the milestone, according to reports.