A new exhibition with an immersive film to reveal the instrumental role of codebreakers in D-Day landing of Normandy opens Thursday at Bletchley Park (BP), UK’s secret intelligence base during the World War II.

The exhibition D-Day: Interception, Intelligence, Invasion, was based on newly declassified material and the first in-depth analysis of BP’s role in Normandy landing. It unveils how, using sophisticated codebreaking techniques, workers at BP fed crucial information to Allied forces in the critical months, weeks and days leading up to D-Day on June 6, 1944.

David Kenyon, research historian at BP, said, “This exhibition portrays the vital link between the men and women at Blethley Park, and their counterparts on the battlefield, and shows how good intelligence could make the difference on the beaches of Normandy between life and death, success and failure.”

BP, located in Buckinghamshire, was where German military signals encoded by the Enigma and Lorenz machines were cracked using pioneering digital computing technology. By 1944 it had become an intelligence factory employing almost 10,000 workers, including big names like Alan Turing. Working in shifts around the clock, they coordinated intelligence gathering from enemy messages sent by Germany, Japan, Italy and beyond.

According to the official historian of British Intelligence, the intelligence produced at Bletchley shortened the war by two to four years. It is also the birthplace of modern information technology. The automatic machinery used to help with decryption was later culminating in the development of Colossus, the world’s first programmable digital electronic computer.

More recently, BP has been open to the public and houses interpretive exhibits and rebuilt huts as they would have appeared during their wartime operations. The new exhibition was launched to coincide with the 75th anniversary of D-Day.