Surgeons in the UK have been training doctors in the Ukraine via video

"I hope to God you will not need to apply this knowledge but it is always best to be prepared for the worst," said one of the leading UK surgeons.

As the conflict in the Ukraine intensified over the weekend, renowned UK surgeons were busy delivering a crash course to doctors on the ground.

General and vascular surgeon David Nott - described as knowing " more about war surgery than perhaps anyone on earth"- worked alongside neurosurgeon Henry Marsh to deliver 12 hours of conflict surgery teaching via video call.

He told the BBC of how he was trying to cram 30 years of experience working in war zones around the world into those 12 hours: "I've been there, I've been cowering when bombs have been coming in, I've been working in underground hospitals. I know what it's like and I know what they'll be facing."

Whilst the teaching was under way inside a conference room in west London, hundreds of doctors working in Ukraine took notes as they sheltered against the conflict and sirens rang out.

"I hope to God you will not need to apply this knowledge but it is always best to be prepared for the worst," said Marsh addressing the doctors thousands of miles away.

He described his feelings of horror and disgust at what was happening in the country, telling BBC reporter, Jonny Dymond: "I'm afraid all the information he's [Nott] going to share with them over the course of a day is probably going to become horribly relevant. It already is in towns like Mariupol which has been shelled to bits."

Both Marsh and Nott spoke of how they wanted to do their bit, even if they couldn't join the medical teams on the ground. "It's the only way we can do it at the moment. We can't go in and we can't go there and operate with them," said Nott, stating that he hoped the internet connection would hold out for the course. 

While the doctors being taught in the Ukraine already have some knowledge of trauma and conflict surgery, it's not something they previously would have had to put into practice. "War surgery is something completely different, because you need to have a mindset about war," explains Nott. 

One of the doctors taking part in the course in a northern suburb of Kyiv, Dr Yuriy Samonenko, told Dymond of his sadness and fear. "Most of these things I know but those pictures are frightening me," he said of the graphic details contained in how to deal with gunshot wounds and blast injuries.

"It's a disaster. I cannot describe my feelings about it. I'm very sad about it because all of these people will have to suffer and die for nothing."

There have also been attacks on Ukrainian healthcare facilities, according to the World Health Organization. Such attacks, they say are "violations of international humanitarian law".