Bletchley Park was the nerve centre of the code breakers

The Bletchley Park Story is part of the first of three development phases at the National Codes Centre's new exhibition complex, called Block B.

The new display tells the story of wartime code-breaking at Bletchley.

It includes the restored Hut 8, in which Alan Turing and his team cracked the Germans' vital Enigma code.

Enigma was the backbone of German military and intelligence communications, and Turing's cracking of it in 1939 is seen as one of the great intellectual achievements of the 20th Century.

The development at Block B also includes an exhibition telling the story of code breaking at the stately home, which historians say shortened the war by two years.

It's a great day for Bletchley Park volunteers who so wanted to make this day happen Christine Large

This includes an interactive display of a German U-boat Enigma station and an Enigma machine.

Also on display for the first time at the official opening by the Duke of Kent was a piece of an original Colossus code breaking machine, which provided information essential to the planning of the D-Day landings.

The Colossus cracked the Lorenz code, which was used by Hitler to communicate with his generals, admirals and air marshals about troop movements.

Speaking after the opening, Christine Large, trust director, said: "It's a great day for Bletchley Park volunteers who so wanted to make this day happen and for the World War II veterans who saw the park really come to life.