Pine processionary moth (PPM), Thaumetopoea pityocampa, is found in Europe including parts of France. The caterpillars build nests where they live communally, feeding throughout the winter on pine trees and occasionally some other conifer species. However, one population of larvae in a limited part Portugal has larvae which develop rapidly during the summer months, and overwinters as pupae. Like other processionary moths, older caterpillars have urticating hairs which can cause rashes and other unpleasant reactions in humans and other animals. During the last 25 years, the pine processionary moth has been increasing its range, spreading northwards in France, and is now found in the area around Paris as well as parts of Brittany. This northwards expansion in range has meant that this moth is of increasing concern to the UK. This PRA is an update of the PRA written in 2012, and includes detailed climate mapping for the southern part of the UK, in order to help assess the risk T. pityocampa poses to this area.