P1010398

P1010398

Observation - P1010398 - UK and Ireland. Description: Caterpillar feeding on pelargonium, must have been already on plant when plant brought indoors for winter. Have observed similar caterpillar on same plant in previous autumns. Please can someone identify for me?

Caterpillar feeding on pelargonium, must have been already on plant when plant brought indoors for winter. Have observed similar caterpillar on same plant in previous autumns.
Please can someone identify for me?