Abstract
A procedure for including the effects of core polarisation in transition probability estimates for nonpenetrating states in multi-electron atoms is described. By combining the non-penetrating transition moment parametrisation of Hameed (1969) with the familiar spectroscopic term value polarisation formula, an analogous formula for correcting hydrogenic transition probabilities is obtained. The procedure is used to estimate lifetimes for non-penetrating states in S V and Cl VI and the corrections are compared with experimental accuracies.