The records of strandings of the harbour porpoise (Phocoena phocoena) on British coasts were analysed for the period 1913-1979. No significant upward or downward trend was found for the record as a whole, but there are significant fluctuations. 1940-43 may represent a particularly low period and 1932-39 a particularly high period. Different seasonal patterns were found on west and east coasts: the Cumberland and South Wales records showing a late summer peak, while the east England records showed a different pattern, possibly a north-south movement. The regional record over the whole period shows that the Cumberland records were not evident for the first 20 years and that the east England records were most numerous during the same period. In discussing these findings the importance of resolving various problems, including identification, observer changes and environmental changes is emphasised before statements can be made with authority about possible trends in the records. Further work is then necessary before any trends can be related to the population alive at sea.