Barton was commissioned to carry out research into the identities of World War I casualties discovered in a mass grave at Fromelles in France, and received access to the Geneva-based Red Cross headquarters basement, the first researcher to see these records.
Details deal with capture, injuries, death, or field burials of servicemen from more than 30 countries, and sometimes include personal effects, home addresses and grave sites. The Red Cross received these details from the combatants; volunteers recorded details before sending them to the home countries.
Some of the records refer to other mass graves, with exact directions as to where they were dug, and the identities of the soldiers who were buried. Where possible, the registers include home addresses and next of kin.He examined records untouched since 1918 and estimate there could be as many as 20 million records in the old cardboard boxes filled with thousands of index cards and hundreds of registers, compiled between 1914-1918.
The Red Cross must now address preservation and digitization of the paper records. Two million pounds has been earmarked for the project which will start in the fall, and will involve experts from all over Europe. The organization says it will almost certainly ask for volunteers to join their own archivists.
According to Peter Barton, the UK's copies no longer exist, but the originals are still here and are immensely important.
"To a military historian, this was like finding Tutankhamen's tomb and the terracotta warriors on the same day," he told me.
"I still can't understand why no-one has ever realised the significance of this archive - but the Red Cross tell me I'm the first researcher who has asked to see it."
The records could potentially reveal the whereabouts of individuals whose remains were never found, or never identified. Grave after grave in the World War I cemeteries mark the last resting place of an unknown soldier.
The organisation's head of press, Florian Westphal, admitted they had never faced a challenge quite like this: "First we have to make sure that we preserve the original records," he told me. "Then, this autumn, we will begin the process of digitising the World War I section of the archive - we expect that phase of the project to cost around four million Swiss Francs."According to the Red Cross, it hopes to have the archive online by 2014, a century after the start of WWI. Those records and today's technology will unlock a piece of history.
There may be more to come, as this careful record-keeping extended through World War II, and to more recent conflicts. There are many more index cards in more boxes on more shelves.
Read the complete story at the link above, and see the video on the same page which covers Barton working with the records.