  We investigate effect of a test magnetic field on the process of destroying
near-extremal Kerr black hole with a charged test particle. It has been shown
that it would be possible to throw a charged test particle into the near
extremal rotating black hole and make it go past the extremality i.e. turn Kerr
black hole into the Kerr-Newmann naked singularity. Typically in an
astrophysical scenario black holes are believed to be surrounded by a magnetic
field. Magnetic field although small, affects motion of charged particles
drastically due to the large Lorentz force, as the electromagnetic force is
much stronger that the gravity. Thus a test magnetic field can affect the
process of destroying black holes and restore the cosmic censorship in the
astrophysical context. We show that a test magnetic field would act as a cosmic
censor beyond a certain threshold value. We try to gauge the magnitude of the
magnetic field by comparing its energy density with that of the change in the
curvature induced by the test particle. We find that the magnetic field
required in only as strong as or slightly stronger as compared to the value for
which its effect of the background geometry is comparable to the tiny
backreaction as that of the test particle. In such a case however one has to
take take into account effect of the magnetic field on the background geometry,
which is difficult to implement in the absence of any exact near-extremal
rotating magnetized black hole solutions. We argue that magnetic field would
still act as a cosmic censor.
