'I'm a World War buff and one thing about WW2 still astonishes me'

Lorraine star Dr Hilary Jones has just released the third and final book in his World War trilogy. Under Darkening Skies wraps up the story that began with Frontline, set in the First World War and telling the story of nurse Grace, who volunteers on the Western Front. Next came the interwar years, charted in Eye of the Storm. The final book, meanwhile, wraps up Grace's story in WW2 - and charts the discovery of penicillin that helped thwart the Nazis.

The book begins in 1937, but charts everything from the birth of the NHS to penicillin's role in the conflict. But even as a World War buff, Dr Hilary confessed exclusively to Express.co.uk that he was still take aback by some of the things he learned.

The ITV star said: "The story about the production of penicillin is a fascinating one - not just because of the medical implications, but because of the sheer serendipity of how it came about. It nearly didn't come about at all, for lots of reasons. It was incredibly difficult to produce it. Alexander Fleming who discovered penicillin didn't really know what he'd discovered - he didn't do anything with it, he didn't test it out on animals, he didn't see it as a therapeutic agent. He thought it might be useful in the laboratory to make cultures of other bugs.

"It was much later when a group of Oxford scientists said, 'There could be something in this stuff'. Even a teaspoon took them years and years to produce, and then when they first tried it on the first six patients, three of them died. By today's standards it would never, ever have been looked at further than that.

"But they realised those three patients didn't die because of penicillin but for other reasons and they persevered, and with the help of the Americans it was produced in time for the D-Day landings and the Tripoli invasion. The book incorporates the fact that we had to send agents into Europe to stop the Nazis getting hold of it first. It was a fascinating story and I couldn't wait to write it."

The author added: "I loved doing the research, I found out so much. There were things that were amazing to me. For example, I had no idea that in 1948 when the NHS was finally brought into being, nine out of 10 doctors voted against it.

"Nye Bevan, at the time, wanted to give something back to the people who had sacrificed so much in the Second World War, particularly the working classes, and wanted to change the system where if you couldn't afford private medical care, you couldn't get any medical care for your family. So many died young.

"But nine out of 10 doctors voted against it, they wanted to keep their private medicine and their independence, they didn't want to be employees of the state. The British Medical Association said 'No, we don't want it'. It was only because they were able to keep their independent contractual status as people who had a contract with the government for the NHS but weren't employees that it ever came into being."

There's more. Dr Hilary was left stunned by one of the tactics used by the Army in WW1, explaining: "I didn't know, for example, that in No Man's Land in the First World War, they actually built artificial trees, because all the other trees were blown to pieces in the bombings, and in order to have snipers and lookout posts, they actually took photographs of tree stumps, had them recreated and set up in No Man's Land so they could stick a soldier in there to be a lookout."

He went on: "I found out that the person who invented Zyklon B, which the Nazis used in gas chambers, was a Jew himself who was a soldier in the First World War and then invented this poison gas which was later used by the Nazis in the concentration camps of the Second World War. That irony is shocking, a quirk of fate.

"There were also lots of medical things - I hadn't realised that the techniques for amputations... more men died from infection than they did of the actual wounds. I learned how they did amputations so quickly in order to prevent infections and how prostheses for men who'd lost their limbs came on in leaps and bounds by necessity because of war."

Dr Hilary's book Under Darkening Skies is released on July 31st and is available from all good bookshops.