[en] Lifetime of levels in ²²⁵Ra, ²²⁵Ac, and ²²⁷Ac have been measured by delayed coincidence techniques and these have been used to determine the E1 gamma-ray transition probabilities. The reduced E1 transition probabilities. The reduced E1 transition probabilities in ²²⁵Ra and ²²⁵Ac are about two orders of magnitude larger than the values in mid-actinide nuclei. On the other hand, the E1 rate in ²²⁷Ac is similar to those measured in heavier actinides. Previous studies suggest the presence of octupole deformation in all the three nuclei. The present investigation indicates that fast E1 transitions occur for nuclei with octupole deformation. However, the studies also show that there is no one-to-one correspondence between E1 rate and octupole deformation. 13 refs., 4 figs