  Inclusive jet differential cross sections for the reaction e+ p --> e+ + jet
+ X with quasi-real photons have been measured with the ZEUS detector at HERA.
These cross sections are given for the photon-proton centre-of-mass energy
interval 134 < W < 277 GeV and jet pseudorapidity in the range -1 < eta(jet) <
2 in the laboratory frame. The results are presented for three cone radii in
the eta-phi plane, R=1.0, 0.7 and 0.5. Measurements of dsigma/deta(jet) above
various jet-transverse-energy thresholds up to 25 GeV and in three ranges of W
are presented and compared to next-to-leading order (NLO) QCD calculations. For
jets defined with R=1.0 differences between data and NLO calculations are seen
at high eta(jet) and low E_T(jet). The measured cross sections for jets defined
with R=0.7 are well described by the calculations in the entire measured range
of eta(jet) and E_T(jet). The inclusive jet cross section for E_T(jet) > 21 GeV
is consistent with an approximately linear variation with the cone radius R in
the range between 0.5 and 1.0, and with NLO calculations.
