16 February 1999. Thanks to AJ.
Source: http://www.ft.com/hippocampus/q1279d6.htm

Financial Times, February 16, 1999

STATION X: Enigma variations
By John Munch

STATION X: The Codebreakers of Bletchley Park
by Michael Smith
Channel 4 Books £14.99, 184 pages

It was almost 30 years after the end of the second world war before the wartime codebreakers of Bletchley Park were allowed to break their cover and recount what is now recognised as the greatest single British contribution to the Allied victory.

The first to go into the public domain was a Group Captain F.W. Winterbotham, who disclosed the extraordinary achievement of the codebreakers in providing a stream of so-called "Ultra" intelligence, the British cover-name for all high-grade signals intelligence derived from cracking the German Enigma code.

Winterbotham's slim volume of wartime memoirs, which appeared in 1974, came in for some heavy criticism. This was in part because it contained apparent inaccuracies, but also because some of his colleagues felt he should never have gone into print at all.

One of these Bletchley colleagues many years later recorded his dismay over Winterbotham's decision to publish. "I was shocked to the point of refusing to read the book. . . and to this day I feel inhibited if by chance the subject comes up; my wife said she found difficulty in marrying a man who would not tell her what he did in the war."

It was the obsessive and instinctive guardedness of this kind that allowed the almost miraculous preservation of Bletchley's secret source of information throughout the war - and well into the cold war, too, when the cyrptanalytical techniques developed there were directed towards a new enemy, Soviet communism.

They were helped by the unshakeable German conviction that the Enigma codes - several variants were used by each of the three armed services - were impossible to break.

Ultra's contribution did not begin until the spring of 1941, as the Enigma cipher was progressively decoded. The effect was powerful, if not always decisive, in the fluctuating north African campaign.

By the time of the battle of Alamein, Ultra's influence was less powerful than the decisive superiority - 5 to 1 - in tanks and airpower enjoyed by the Allies. The disappointment felt at Bletchley was that, given the constant stream of intelligence being supplied to Montgomery at the time, he was not able cut off Rommel's retreat before he reached Tunisia.

Its influence in the war against the U-boats - where the naval Enigma was broken from the second half of 1941 - helped provide the information about U-boat locations to re-route convoys to safety. It has been calculated that about 1.5m tons of shipping were saved and valuable time was bought to build new ships and develop more effective anti-submarine defences.

Michael Smith's book accompanies a four-part Channel 4 series on the wartime codebreaking centre, and it has some of the faults that inevitably beset the "book of the film" genre. Its anecdotal and generalist style will suit those coming to the subject for the first time. But quotations on a printed page from the codebreakers cannot rival the pathos and potency of seeing spry Bletchley Park veterans, speaking to camera, reliving the exhilaration of breaking Enigma. Nonetheless, if Station X can point a new generation in the direction of the Bletchley Park literature, it will have served a useful purpose.

The Codebreakers of Bletchley Park by Michael Smith, Channel 4 Books, £14.99, 184 pages