Fossil monkeys are rare in the British palaeontological record, a few specimens having been reported from the Pleistocene, and a single specimen from the Red Crag, possibly of Late Miocene or Pliocene age. An undescribed monkey tooth from the Red Crag at Waldringfield collected circa 1908 that has remained unidentified in the collections of the Sedgwick Museum, Cambridge, is described herein. The fossil was associated with dental remains of a suid, a tapir and a deer which, taken as an assemblage, are best correlated to the Early Pliocene, being similar to specimens from Perrier, France. Because of the high latitudinal position of Waldringfield (52°N) and indications for a tropical to sub-tropical palaeoenvironment during the Late Miocene – Early Pliocene, the monkey tooth from there is of great interest.