SImPSON | 137
figure 13.3 The Banburies found in the roof: Banbury Two.
Reproduced with permission of the Bletchley Park Trust. © Bletchley Park Trust.Human fallibility is illustrated too. Holes have been punched on both G and W in column 83,
on both B and T in column 112, and on none at all in column 113 of Banbury One: there should
have been precisely one hole in each column. Another of the working papers has written on it:
Wheel orders 321 & 123 appear to have punches wrongly punched.
A second hand has ringed this in red and added:
To all [word illegible] very concerning.
Questions abound. For one thing, how could such a blatant breach of security have occurred?
The rule was absolute that every scrap of working paper must be locked away when a room was
even briefly unoccupied. We know the two points in the Hut 6 roof where the papers were
found, but not which staff were occupying the rooms beneath in 1940. Joan Clarke recalled one
proper means of disposal in Hut 8:^10
Chores performed in the slack periods included removing pins and tearing up the Banbury
sheets for solved days, and other workings, as required for re-pulping.
Weather reports do not in fact endorse the conjectured purpose of stopping a draught. There
had been intense cold during the preceding winter when Hut 6 was being constructed: the cold-
est January since 1838 at nearby Oxford. Mid-February continued very cold with snow, and this
lasted into early March. April was on the whole dull and wet, warm in the last week, the time
of the dated papers; and May’s temperatures substantially exceeded the average. But no more
plausible explanation can be offered.
And why in Hut 6? For technical reasons arising from the cipher systems, Banburismus was
neither needed nor used against the Army and Air Force Enigma broken in Hut 6, but only
against the Naval Enigma dealt with in Hut 8. Here we do have a clue. Mahon wrote in his
history that:^11
Work was fizzling out when Norway was invaded and the cryptographic forces of Hut 8 were
transferred en bloc to assist with Army and Air Force cyphers.
Further light is shed by occasional references in the other papers found in the roof. There is
frequent use of the verb ‘shove’ in such contexts as ‘shoved and tested’ and ‘shove anew’. These,
along with the already mentioned ‘punches not punched’ and other textual details, are terms