"If you go to the battlefield at Verdun, you can see exactly why the EU was going to be formed. We don't want to fight wars like this again."

Colonel Richard Nunneley knows a thing or two about war. The tall, sharp-suited, and impeccably spoken former soldier is a trustee of London's National Army Museum. He's also a veteran of armed combat.

"Torso in Metal from 'The Rock Drill'" by Sir Jacob Epstein, 1913-4

He recently visited what he says is an important exhibition just off London's Trafalgar Square, an exhibition that not only reflects directly on World War I, but indirectly on all armed conflict, past and present.

Part German himself, and with a German wife, Nunneley says it's vital to remember that the First World War wrought carnage on all nationalities.

"I think we should talk about [World War I]," Nunneley says, "because after all, grief on one side is just as great as on both sides."

Remembrance through experience

The colonel insisted all of his children visit World War I battlefields to ensure they understood war's brutal reality. Since leaving the army, he has been actively involved in educating others about war's tragic consequences.

"In the National Army Museum we put on an exhibition on mutilations and the birth of plastic surgery," said Nunneley. "We had a lot of criticism (…) but we said that our job is to reflect reality. War is a bloody awful thing."

Nunneley was one of thousands flocking to London's National Portrait Gallery to be reminded of the bloody, awful nature of war. "The Great War in Portraits" is an exhibition of images of individuals involved in the "war to end all wars." It commemorates the centenary of the shockingly brutal conflict.

Ripples felt today

"A Grenadier Guardsman" by Sir William Orpen, 1917

Known for its extraordinary losses and destruction, The Great War changed the imperial, political and military structure in place at the beginning of the 20th century. Yet this exhibition isn't about politics or military maneuvers, says its curator, Paul Moorhouse. It's about the human experience of war.

"On the first of July, 1916, at the end of the first day of the Battle of the Somme, 19,240 British soldiers were dead. The number trips off the tongue, but how do you comprehend that?" he asks. "You have to give a human face to it."

It's this human element of the war that holds the real fascination, says Penny Hamilton of London as she walked past photo images and "postcards" of military figures, to striking oil paintings, to British and German propaganda videos in the exhibition.

"There was a loss in nearly every family," Hamilton says. "It was an equal opportunities war for casualties, and so there is a great interest (…) never mind whose fault it was. The fact was that it was just cataclysmic for all nations."

Human element of war

Self-portrait by Sir William Orpen, 1917

The human faces on display - some haunted, some smiling, others partly reconstructed after mutilation - reveal the intense suffering of The Great War. The exhibition opens by contrasting regal portraits of the national leaders of the time, and power portraits of military commanders, with images of soldiers whose names were not recorded. Such images have much in common with soldiers of the 21st century, Moorhouse says, who are simply "part of the rank and file, lost in history."

But "the empirical and emotional core of the exhibition," says Moorhouse, is The Valiant and the Damned photo installation that focuses on individual stories of those participating directly in the conflict, or involved indirectly. A single wall covered by 40 individual snapshots - pieced together as one installation - lists names, if known, and details each often-tragic ending, such as that of Private Harry Farr.

After serving bravely for the first three years of the war, Farr reached a breaking point - probably due to what's been called shell shock, or post traumatic stress disorder - and refused to continue fighting. As a result, he was executed for cowardice in the face of the enemy in 1916, one of 306 British soldiers of the First World War "shot at dawn" for cowardice or desertion.

Shocking imagery

Self-portrait as a soldier by Ludwig Kirchner, 1915

A particularly harrowing aspect of the exhibition is a section on facially mutilated soldiers, including images long hidden from the public. An image of 2nd Lt. R.R. Lumley's bloodied drooping eye is particularly poignant. Exhibition curator Paul Moorhouse describes the stigma surrounding the suffering of soldiers whose faces were, and sometimes still are, shattered by war as "an appalling writing out of a certain vital, human element in the story."

"It was acceptable at the time to appear in public missing an arm or a leg," he says. "Those mutilations were seen as badges of courage and duty. But if you had your face shot away, it robbed you of your identity…(and) the capacity of other people to look at you. Even members of their own family couldn't bring themselves to look at them. So we're bringing them back and restoring them to their rightful place in the narrative."

Some of the images are not for the faint of heart. Yet the exhibition has "really captured people's imaginations," says Moorhouse. Seeing individual suffering is so different to reading dry facts and historical stats, says Emily Tate from Manchester, who was in London visiting her sister.

It's not all doom and gloom, though.

"Although there is this violence, cruelty and bitterness, there are portraits that show you the opposite, which are the ennobling characteristics of humanity - heroism, selflessness, the ability to laugh under appalling conditions and a kind of unimaginable endurance under incredible adversity," says exhibition curator Paul Moorhouse. "And that to me is an extraordinarily positive aspect of human nature."

Brutality still happening

"The Dead Stretcher-Bearer" by Gilbert Rogers, 1919

"This exhibition is so different to learning about it in a history book," says Tate. "And it's like ‘Oh, so that did actually happen to people.' And that kind of stuff is still happening to people all over the world."

With the situation currently evolving in Crimea, the question of whether any lessons were learned from The Great War is particularly pertinent, says exhibition curator Paul Moorhouse. The exhibition runs until June 15.