Measurements of total ozone at Halley Bay, Antarctica, are presented for the six most recent observing seasons, 1980‐86, showing the consistency and progress of the spring ozone depletion. The principal ozone minimum of October 1985 was as deep as that of 1984, if not deeper. However, the period of depletion was affected by strong wave activity, giving rise to four distinct minima. A cusped maximum in total ozone was observed at Halley Bay on 19 October 1985, confirmed by temperatures in the lower stratosphere and by a similar ozone maximum at Faraday station, Argentine Islands. In the presence of such fluctuations, it is not possible to say whether the ozone depletion has reached its limit or not: indeed several years' data will yet be needed before that question can be answered. Ozone amounts recorded in the summer period December 1985 to February 1986 remain marginally lower than in the past.