  The ZEUS detector at HERA has been used to measure the photoproduction of
isolated photons in diffractive events. Cross sections are evaluated in the
photon transverse-energy and pseudorapidity ranges 5 < E_T^gamma < 15 Gev and
-0.7 < eta^gamma < 0.9, inclusively and with a jet with transverse-energy an
pseudorapidity in the ranges 4 < ETjet < 35 GeV and -1.5 < etajet < 1.8, for an
integrated luminosity of 374 pb^{-1}. Further kinematic variables studied
include the fractions of the incoming photon energy and of the colourless
exchange ("Pomeron") energy that are imparted to a photon-jet final state.
Comparison is made to predictions from the RAPGAP Monte Carlo simulation.
