9314792 Durney The Babcock-Leighton theory of twenty years ago holds that the migration of magnetic fields across the solar surface plays a key role in the reversal of the solar magnetic field. However, more recently, the idea that the reversal has its origin at the base of the solar convective zone has become widespread. This implies that the observed surface activity is irrelevant to this question. A study will be undertaken to establish whether the Babcock-Leighton theory is in fact viable or should be abandoned. ***