  In this paper we consider external current QED in the Coulomb gauge and in
axial gauges for various spatial directions of the axis. For a non-zero
electric charge of the current, we demonstrate that any two different gauges
from this class correspond to quantum theories which are not unitarily
equivalent. We show that the spacelike asymptotic flux of the electromagnetic
field is the underlying superselected quantity. We also express the large gauge
transformation linking two distinct axial gauges by the Wilson loop over a
contour limited by the two axes. Thus the underlying physical mechanism appears
to be related to the Aharonov-Bohm effect.
