It’s flat, pitted, cardboard-like, and some forgotten soldier in Gallipoli in 1915 took a nibble from one corner before deciding it would better serve as a postcard.

“Happy Xmas from the Dardanelles 1915,” the man wrote in pencil.

This tiny relic, which speaks volumes of the courage, humour and adversity in the Gallipoli trenches, is one of 1300 objects in the brand new permanent First World War galleries in London’s Imperial War Museum.

The IWM reopens this Saturday after a £40 million ($73.22 million), six-month renovation which tripled the size of these galleries as well as reinventing the museum’s central atrium with a dramatic display of planes, guns and tanks, including a Spitfire fighter and a V1 rocket.

One of the prizes of the collection is a Lancaster bomber cockpit, from ‘Old Fred’, flown by 467 Squadron Royal Australian Air Force, which took part in 49 sorties over enemy territory in 1943-44.

In the First World War Galleries, Australia is represented by the flag of the 12^th Battalion Australian Imperial Force, whose 1000 soldiers went ashore at Gallipoli at 4.30am on 25 April 1915.

Within five days, more than half were killed or wounded – but the blue and white woolen flag, which went on shore in the first wave, survived, stained and worn but intact.

It may have been the first flag carried ashore in the Gallipoli campaign, though it is unclear when it was first raised.

Now it flies above the little army biscuit, and next to a uniform worn by an ANZAC private from 1^st Battalion.

The note on the display reminds visitors of the deaths at Gallipoli – “long, sad rows of eternally silent figures, their drenched and blood-stained khaki drying in the sun.”

Said IWM’s Laura Clouting, who curated the World War I galleries, “this flag really sums up that traumatic campaign and how difficult it was for Australia troops, for British troops.”

Ms Clouting said she wanted British visitors to shake up their stereotypes of the war.

“We often think of the Western Front and trench warfare but we never really think about the other fronts and we wanted to overturn that in the new galleries,” Ms Clouting said.

“It’s often a perception of mud and rain and cold, whereas in the Gallipoli campaign the heat is unbearable, and there are the flies.”

To illustrate these mundane irritations of war the case also contains the horse hair fly whisk carried by General Sir Ian Hamilton, commander in chief of the Mediterranean Expeditionary Force at Gallipoli.

“At the Dardanelles it was always in my hand,” he wrote.

Lead curator James Taylor said the IWM renovation, and the Great War galleries in particular, were the result of four years’ intensive work, aimed at explaining to new generations who could not hear stories firsthand any more, why the war started, why it continued, how it ended and what its impact was.

The displays include the words spoken or written at the time, in recordings, diaries and letters. They deliberately did not include anything written in memoirs with the benefit of hindsight.

“Nothing was certain in this war,” he said. “The First World War meant four years of surprises and four years of shock. We felt it hugely important that our galleries should reflect that.”