By early 1942, the trickle of intercepted Avwehr telegrams had become
a flood. This was largely the work of Dilly Knox, who had succeded in
penetrating the secrets of the cypher machine used by the Abwehr. This
comprehensive system of eavesdropping yielded fascinating glimpses of
the intimate life of German intelligence officers. There was the case,
for instance, of Axel, the German police dog. He had been posted from
Berlin to Algeciras, presumably to guard the Abwehr out-station there
from British agents sneaking across the bay from Gibraltar. On the
last stage of its journey, Madrid sent a warning telegram to Albert
Carbe, alias Cesar, the head of the Abwehr post at Algeciras: 'Be
careful of Axel. He bites.' Sure enough, a few days later, Algeciras
came up with the laconic report: 'Cesar is in hospital. Axel bit him.'


   -- Kim Philby
      My Silent War
      1968