The organ and effective dose to male and female MIRD-5 type stylised phantoms representing adult human bodies have been calculated for environmental photon exposures in idealised source term geometries. The radiation scenarios considered are: air submersion in a radioactive cloud, contamination deposited on the ground surface and radioactive material deposited to a depth of 1 cm in the ground. The calculations have been made for a number of radioactive nuclides in each scenario considering their importance in a radioactive fallout situation. The radiation doses and the corresponding statistical errors calculated in this work are shown to be comparable to internationally established data. The benchmark indicates that the male (MCAP3) and female (FCAP3) phantoms used by the Swedish Defence Research Agency coupled with the dose determination algorithms used in this work produce reliable organ and effective dose data for the radiation scenarios considered.