'Enigma and the Ruthless plot' - letter in The Times

From The Times
April 18, 2008

Enigma and the Ruthless plot
----------------------------

The cancellation of Operation Ruthless was a great disappointment to 
Bletchley Park

Sir, The cancellation of Operation Ruthless in October 1940 ( report,
April 7 ), was met with dismay in Bletchley Park. Much store had been 
set by this opportunity to assist in the recovery of the daily key of 
the German naval Enigma, which was proving extremely difficult to 
resolve.

Frank Birch, head of the naval section in Bletchley Park, had described
Ruthless as a "very ingenious plot" : it gave away nothing if it failed.
On October 20 he wrote to a colleague : "Turing and Twinn came to me 
like undertakers cheated of a nice corpse two days ago, all in a stew 
about the cancellation of Operation Ruthless. The burden of their song 
was the importance of a pinch. Did the authorities realise that, since 
the Germans did the dirt on their machine on June 1 ( ie, changed the 
method of assembling the key ), there was very little hope, if any, of 
their deciphering current, or even approximately current, enigma for 
months and months and months - if ever ? Contrariwise, if they got a 
pinch, even enough to give a clue to deciphering one day's material, 
they could be pretty sure, after an initial delay, of keeping going 
from day to day from then on..."

Ian Fleming told Birch that the value of a pinch was well recognised and 
that Ruthless had only been postponed. It was never to be revived. Not 
to be denied, in May and June 1941, at the instigation of Harry Hinsley, 
another member of the naval section in Bletchley Park, two German weather 
ships off Iceland were deliberately targeted and captured by the Royal 
Navy. The cipher material obtained was to be of immense importance in 
breaking the German naval Enigma daily key settings.

Full details of Operation Ruthless can be found in the National Archive.

Peter Wescombe
Bletchley Park Trust 


http://www.timesonline.co.uk/tol/comment/letters/article3767257.ece