Your large green caterpillar with white diagonal stripes belongs to one of the hawk-moths, probably the privet hawk-moth. It is apparently not a common insect, although it would normally be difficult to see if quietly feeding in a shrub or tree. At The Courier we receive only one or two reports from readers each year. Despite its name, its caterpillars feed on more than privet. They also feed on jasmine and other plants.

The unusual and prominent spine at the tail end is harmless.

Caterpillars can grow to eight centimetres long. The size of the caterpillar indicates whether it is fully grown and ready for pupation. It will emerge as a large, mottled grey-brown moth with a 10 – 12 cm wingspan.