Free The Secret Life of Bletchley Park by Sinclair McKay Page B

Norway campaign, the army and air force codes, and separate air force training codes. The time and the frequency of each message would be noted down on vast sheets of paper, leading to an immediate strain on the Park’s supply of coloured pencils. But the colour keys were a stroke of organisational genius – a vivid signifier that allowed everyone to identify each key with ease. Indeed, Welchman recalled in his memoir that one element of recruitment to Bletchley Park involved asking candidates ‘if they were colour-blind’.
    In our world of ubiquitous touch-screen technology, such a system smells of pencil shavings and glue and bits of string. But it worked. The avalanche of thousands upon thousands of intercepts – the numbers of which would multiply dramatically as the PhoneyWar ended and the conflict intensified – had order imposed upon it. It could be deduced from which part of the German military they were being sent, and to which.
    It soon became necessary to develop subdivisions for the keys (such as SS messages, and messages to do with German railways); before long every colour in the rainbow was deployed. When all available colours had been used, keys were named after marine life: birds; then elephants; and insects …
    There were many occasions when a message could not be broken in its entirety, because words were missing or incomplete. As a result, a comment would be added with the words ‘strong indications’, ‘fair indications’ or ‘slight indications’ to convey the varying degrees of the decrypt’s reliability. But it was through the work of Chatham – and later other intercept stations such as Denmark Hill in south London – that Welchman began to understand about the different call-signs used by different operators, and what signs would be used for what sorts of messages.
    Dilly Knox was also using the period of the Phoney War to get himself and his team ready for the onslaught of work that was to come. The difference between Knox and Welchman was Knox’s apparent taste for pulchritude on his team, although now Mavis Batey laughs off – with a very faint edge of annoyance – any idea that she was recruited chiefly for reasons of glamour: ‘Dilly was very firm. He said he did not want any debutantes who had got there by Daddy’s knowing someone in the Foreign Office. Equally, he said, he didn’t want a yard of Wrens who all looked alike and you couldn’t tell one from the other.
    â€˜As for Dilly going around picking out girls, that is totally untrue. We were all interviewed by this dreadful Miss Moore, a fierce lady in the Foreign Office.’
    There is another possibility too; that Dillwyn Knox had somehow found that women had a greater aptitude for the work required – as well as nimbleness of mind and capacity for lateral thought, they possessed a care and attention to detail that many men might nothave had. This, of course, is just speculation; the other possibility, and one that seems likely considering the scratchiness of many of Knox’s personal dealings, was that he simply did not like men very much.

    As the war effort intensified, new recruits would be given a statutory three-week induction period to be taught the nuances of code-breaking. Later still, recruits were sent to Bedford for a few weeks, to sit in a dusty, anonymous office where they learnt the rudiments of Japanese, in order to be able to crack the Japanese codes.
    But for that first wave of recruits, Bletchley Park as an institution had what some have described as a peculiarly English air of improvisation, of simply diving in and getting on with it. Perhaps there was no other way. For in the face of a challenge like the Enigma keys and without, at least at first, the technology to be able to attack them mechanically, the Park would need as many original, quirky, lateral thinkers as it could get, and then give them as free a rein as