As battle raged across the fields of Flanders, British soldiers found brief respite from the horrors of the First World War in "underground towns" far below the mud and gore. Now, more than 90 years after the armies left and the extraordinary networks of tunnels were flooded, the task of finally revealing their secrets has begun.

The prize, archaeologists and historians believe, is an unprecedented insight into the lives of British troops on the Western Front.

They believe that, because of the absence of light and oxygen in the flooded tunnels, possessions, such as beds, weapons, helmets, clothing and even newspapers, will have been preserved and will be found exactly as they were left in 1918.