Morris dancing

 was a type of traditional folk dancing practised in England. Within the village of Devil's End, at least, it was usual for morris dancing to mark May Day celebrations. One May Day in the latter half of the 20th century, the Third Doctor was attacked and tied up at a maypole by Morris dancers. (DW: The Dæmons)

The Fourth Doctor told his companion Leela that he hated Morris dancers almost as much as the Daleks and the Cybermen. (BFA: The Wrath of the Iceni)