The mechanical properties of 590 MeV proton irradiated pure cl-iron have been investigated after irradiation at 320, 420 and 520 K to doses between 10(-5) and 10(-1) dpa. For comparison, corresponding rests were carried out on unirradiated iron specimens. Radiation hardening is observed at doses above 10(-3) dpa for all irradiation temperatures and a (dose)(1/4) dependence is found after irradiations at 320 K. It is shown that the irradiation suppresses the dynamic strain ageing observed in the unirradiated iron. The systematic observation of intergranular cracking in the specimens irradiated to doses of 10(-3) dpa or larger is discussed in terms of dislocation channeling. (C) 1999 Elsevier Science B.V. All rights reserved.