1. This paper reviews the status of the freshwater pearl mussel (Margaritifera margaritifera L.) in the British Isles and Continental Europe.

2. The mussel has continued to decline in recent decades throughout the European range, apparently caused mainly by pollution (especially by organic enrichment) and, in the British Isles, by a combination of this and overfishing for pearls.

3. Of particular concern is the almost complete absence of juveniles in most populations, with these occurring in numbers only in a very few rivers in remote locations.

4. M. margaritifera is now completely protected in most European countries and in Britain the government has recently made it an offence to kill or harm the mussel. However, it will still be permitted to take the mussel, examine it carefully for pearls, and then to return it unharmed to the river. This may prove difficult to enforce and it is concluded that it will be ineffective and that complete protection may still be needed.

5. There is no current monitoring programme for M. margaritifera anywhere in its range and without continuing evidence on its status and further research on the habitat requirements of the juveniles, it is difficult to be optimistic about its survival.