The triple gauge boson couplings between two W bosons and a photon have been studied using photonic events with missing energy. The data sample was obtained at LEP with the OPAL detector. The centre of mass energies lie in the range 189-202 GeV with a total luminosity of about 400 pb-1. Constraints on the gauge coupling parameters Delta kappa_gamma and lambda_gamma have been determined by fitting the differential cross section in bins of energy and cos(theta).