the attached document was intercepted by harry steam who have managed to plant a bug on the
communication lines out of tirpitz ufer our crypt analysts have examined the ciphertext and the case
files and believe that it maybe related to the wheatstone clock cipher deputy head of the division
has written a boss guide to these cipher machines and we have added that to the case files harry
steam also recovered a scrap of burnt paper from the abwehr hq waste which carries the following
message which we think might be part of the plaintext tential stop the tripwire option is also
deprecated since it is more likely that the expl the navy reported that a dutch fishing vessel was
impounded by the nazi authorities in bremerhaven the crew were detained and negotiations are
underway between the dutch and german authorities to try to get the fishermen and their vessel back
but in the meantime rn patrols will watch out for the boat in case it is involved in the operation
the air ministry have been briefed on our findings so far and have emphasised the importance of
protecting the rdf system which i am told they call chain home vk is sympathetic but the three of us
are still worried about the new agents embedded in london and we are not sure how much of a threat
they pose it is crucial that we break the attached ciphertext as fast as possible so we can put
effective countermeasures in place it is tempting to arrest all twenty three spy c lists and ask
them directly but without revealing the extent of our surveillance and code breaking ability it will
not be possible to prove that they have broken the law so we would not be able to detain or deport
them it would usually be better to watch and wait but the air ministry feels that the risk to our
air defence is too great so we need to act fast if we knew exactly when and where they intended to
attack chain home then we might be able to increase security to prevent it but again we risk
revealing our counterintelligence capabilities harry suggested that we could obscure our tracks by
faking a visit by dignitaries to the target sites as a coverstory for increased security but we cant
maintain the increase for long without raising suspicion so it is crucial to determine their plans
whatever the abwehr are intending they wont want their agents to fall into our hands especially
after a demolition since that would give us the excuse we need to arrest them it would be good to
know what they have in mind for their exfiltration things are very finely balanced if we act too
soon we giveaway our crucial advantage in the intercept war if we act too late our enemies could
seriously damage our air defence capability it is clear that things are coming to ahead and it is
crucial that we crack the clock cipher as soon as possible the fate of the country lies in your
hands pearl