  An Optical Transition Radiation monitor has been developed for the proton
beam-line of the T2K long base-line neutrino oscillation experiment. The
monitor operates in the highly radioactive environment in proximity to the T2K
target. It uses optical transition radiation, the light emitted from a thin
metallic foil when the charged beam passes through it, to form a 2D image of a
30 GeV proton beam. One of its key features is an optical system capable of
transporting the light over a large distance out of the harsh environment near
the target to a lower radiation area where it is possible to operate a camera
to capture this light. The monitor measures the proton beam position and width
with a precision of better than 500 {\mu}m, meeting the physics requirements of
the T2K experiment.
