Even though knowledge of the tunnel had been passed to the So-
viets by the British double agent George Blake, the intelligence yield
for the British and the Americans was substantial. It included hard
data on Soviet political actions and intentions in Berlin, the Soviet
atomic energy program, Soviet and East European military coopera-
tion under the Warsaw Pact, and Soviet radio intercept operations.
Among the hardest-hit targets were the Soviet military intelligence
and counterintelligence units in Germany, thereby providing invalu-
able information for cross-checking and analyzing information ob-
tained from double agents run by the CIA and other friendly Western
services. Fearful that Blake might be compromised should any coun-
termove be undertaken, the KGB had allowed the transmissions to
continue and even withheld knowledge of the tunnel from their key
representative in Berlin, Yevgeny Pitovranov, until a later date.
Heavy rains in spring 1956 finally gave the Soviets an opportu-
nity to announce their “discovery” of the tunnel. On 22 April, an
investigation of short-circuiting problems revealed the existence of
the tap chamber, even though the digging team only slowly realized
what they had uncovered. Within hours of the tunnel’s discovery, the
Soviet ambassador in East Berlin issued a strong official protest to
the American commander, and two days later, members of the inter-
national press were allowed a firsthand inspection of the “American
spy tunnel.” Soviet authorities made no mention of British complic-
ity, and there is no evidence that the newly formed West German
Bundesnachrichtendienst had also been involved in the operation.
News of the tunnel further intensified the bitter relations that
already existed between East and West Berlin. Willy Brandt, the
leader of the Sozialdemokratische Partei Deutschlands who later be-
came mayor of West Berlin, announced that he would visit the site on
the condition that four political prisoners held in the GDR (including
recently kidnapped Robert Bialek) accompany him. Amid extensive
publicity, Brandt arrived at the Brandenburg Gate on 28 April and,
not surprisingly, found none of the four men. The East Germans soon
turned the site into a popular tourist attraction, replete with guided
tours and a mobile snack bar. By the end of June, however, the tours
had ended. The tunnel entrance was blocked and the Schönefelder
Chaussee resurfaced. On the Western side, the warehouse and other
adjacent buildings remained occupied by the U.S. Army until the32 • BERLIN TUNNEL