 Sabotage operations were ordered from Berlin in the late autumn of 1940 , but actual work did not start until early 1941 . The first operations were unsuccessful . A first attempt to smuggle a bomb into Gibraltar was aborted , as the timing device was faulty . In February there was a large explosion in the North Tunnel , and in April a bomb blew up near the airfield . In June 1941 , however , the British intelligence foiled a new attempt , by a German agent , to attach a mine alongside an Allied cargo ship . Another attempt failed when Plazas placed a bomb inside an ammunition store but was not able to bring the explosive . It was not until 1942 that the operations begun to succeed . In January 1942 , two Spanish agents manage to destroy two aircraft at the North Front landing strip . 
 Sabotage operations <a href='uninflect' title='1'><mark>were</mark></a> ordered from Berlin in the late autumn of 1940 , but actual work did not start until early 1941 . The first operations <a href='uninflect' title='2'><mark>were</mark></a> unsuccessful . A first attempt to smuggle a bomb into Gibraltar was aborted , as the timing device was faulty . In February <a href='dey_it' title='3'><mark>there</mark></a> was a large explosion in the North Tunnel , and in April a bomb blew up near the airfield . In June 1941 , however , the British intelligence foiled a new attempt , by a German agent , to attach a mine alongside an Allied cargo ship . Another attempt failed when Plazas placed a bomb inside an ammunition store but <a href='negative_concord' title='4'><mark>was</mark></a> <a href='negative_concord' title='5'><mark>not</mark></a>able to bring the explosive . It <a href='negative_concord' title='6'><mark>was</mark></a> <a href='negative_concord' title='7'><mark>not</mark></a>until 1942 that the operations begun to succeed . In January 1942 , two Spanish agents manage to destroy two aircraft at the North Front landing strip . 
Sabotage operations was ordered from Berlin in the late autumn of 1940 , but actual wrk did not start until early 1941 . The first operations was unsuccessful . A first attempt to smuggle a bomb into Gibraltar was aborted , as da timing device was faulty . In February it was a bigass explosion in the North Tunnel , and in April a bomb blew up near the airfield . In June 1941 , however , the British intelligence foiled a new attempt , by a German agent , to attach a mine alongside an Allied cargo ship . Another attempt failed when Plazas placed a bomb inside an ammunition store but ain't able to bring the explosive . It ain't untill 1942 dat the operations begun to succeed . In January 1942 , 2 Spanish agents manage to destroy two aircraft at the North Front landing strip .