Every intercepted enemy message … all these encrypted communications, jumbled up into seemingly random letters in groups of four or five, and transmitted by radio, were gathered in the many listening posts around the British coastline.

Shortening World War Two

By Roger Childs

The name Bletchley Park is synonymous with code breaking. It was here during the war that some of the greatest British minds in a generation cracked the Enigma codes and other encryption systems used by the enemy and, in General Eisenhower’s view, probably shortened the war by two years. 

The Enigma machines – compact beautifully designed devices looking a little like typewriters with lights – were used by all the German military forces; these portable machines generated the countless millions of different letter combinations in which most coded German communications were sent. 

Decrypting Enigma meant that the military commanders could be advised in advance of the enemies plans for bombing raids, U-boat movements, moving troops and ships, and invasion plans. However, the success of the Bletchley gurus created a dilemma for the government and military authorities — how to prevent the enemy working out that their secret codes had been uncovered, and subsequently changing their systems.

If the Germans got wind of a city’s defences knowing that a particular raid was coming, the BP code breakers could be back to square one. The government knew that Coventry was going to be attacked in November 1940, but decided not to warn the authorities in the West Midlands city that the bombers were coming. This decision created huge controversy after the war.

The story behind the code crackers

… a portrait of one of the most remarkable brain factories the world has ever seen. Military historian, –Max Hastings

Sinclair McKay’s The Secret Life of Bletchley Park is a superb account of what the thousands of people working at the Buckinghamshire intelligence hub actually achieved. The personnel included, high society women, students out of high school and university, factory workers, typists, Wrens, scientists, mathematicians and inventors. They were all billeted around the towns and villages of the area and were sworn to secrecy.

It was work of unrelenting intensity and carried out in three eight hour shifts per day for over five years in huts that were specially built in the grounds. (All these were demolished after the war.) Teams specialized in the different codes used by the Wehrmacht, German navy, air force and government.  

Among the great minds at Bletchley were: 

  • Alan Turing a pioneer in the development of electronics and the construction of the code breaking “bombe” machines
  •  cryptologist Dilly Knox who had worked on codes in World War One
  • Tom Flowers the inventor of the computer
  • teenage Wren Jean Valentine who was such a success she was sent to Ceylon in 1942 to unravel Japanese codes.

There were also scores of highly talented languages and mathematics professors and students.

Leisure pursuits

In their time off the Bletchley Park personnel were involved in a range of cultural and sporting pursuits – music groups, dancing, play performances, revues, tennis, cycling and skating in winter. The authorities also arranged for musicians, and ballet and theatre groups to perform at Bletchley. 

Not surprisingly, there were romances and relationships often sealed down quiet country roads. In a number of instances relationships led to marriage.

An excellent book

Sinclair McKay has done justice to the heroes of Bletchley Park who were long denied recognition as they were sworn to secrecy for decades after the war ended in 1945. He has tapped into the memoirs of the BP veterans and interviewed scores of people were worked there. An interesting section near the end of the book looks at where many of the personnel ended up in the post-war years.

On the last page he sums up just what the decoders achieved in the early 1940s. Equipped with little more than intelligence, enthusiasm and determination, they got stuck right into the job, persisting until they succeeded.

It will never happen again.