[en] The polarization parameters Σ, P and T have been measured for the process γp → π⁰p in the photon energy range 1300-2100 MeV and c.m. angles between 30⁰ and 110⁰, in an experiment with a polarised beam and polarised target. The results are compared with a recent theoretical analysis which fits data from threshold to 16 GeV. The new data are in general agreement with the analysis, but with some significant discrepancies in detail. (Auth.)