Tommy Flowers; Built Computer to Crack German Military Codes

Tommy Flowers, who developed a pioneering computer that cracked German military codes in World War II, is dead at 92.

Flowers died from heart failure at home in London on Oct. 28, his son Kenneth Flowers said Sunday.

Tommy Flowers was born in London on Dec. 22, 1905, the son of a man who installed baking machines. He showed an early mechanical aptitude and graduated from the University of London with an engineering degree.

Flowers joined the British Post Office, then responsible for all national communications, in the 1930s and experimented in electronic telephone transmissions.

In World War II, he was sent to Bletchley Park, an estate north of London, where mathematicians, cryptographers and other experts worked on breaking German military codes.

Flowers spent 11 months developing Colossus, a 1-ton machine that was able to unscramble coded messages electronically rather than mechanically as had previously been done. The machine became operational in December 1943.

“Colossus had all the characteristics of the computer although it wasn’t thought of as a computer at the time,” Kenneth Flowers said. “It could think and made decisions. Up to then these machines had been used just to make numerical calculations.”

The Colossus machines were a key element in Ultra, the intelligence operation that foiled the Germans. Gen. Dwight D. Eisenhower, the supreme allied commander, credited Ultra with saving “thousands of British and American” lives.

By the D-day invasion June 6, 1944, Flowers had produced another Colossus that worked five times as fast as the original. By the end of the war in 1945, 10 machines were in operation.

During the war, Flowers worked quietly and secretly, not even telling his family the nature of his assignment.

“He told us he worked on something secret and important,” his son said. “They were allowed to tell that much in case their wives wondered where they were. But until the ‘70s he never said anything else. It was a point of honor really.”

After the war, he returned to the post office and tried to persuade his superiors to use technology to produce an all-electronic phone system.

“He spent 20 years trying to persuade them, but he wasn’t so successful because he couldn’t tell them he had already produced the machine,” Kenneth Flowers said.

Flowers received an honor, Member of the British Empire, for his work in the 1940s, but remained largely unknown to the wider public because the work was kept secret until the 1970s. Bletchley Park is now a tourist attraction with a replica of the Colossus.

In addition to his son, Kenneth, Flowers is survived by his wife, Eileen, another son John, and three grandchildren.

The funeral was to be held today at Hendon Crematorium in north London.