Not in the least harmful - its a ladbybird larvae.

unless your a greenfly or aphid lol .

Keepers :o) as said ladybird larvae, loves greenfly and many other pests.

Thanks all! Glad I didn't squash it then. Certainly wouldn't have guessed.

Pete, you are not the only one. They are commonly mistaken for pests.

They look nasty, but are harmless to us, and do good for the garden as larvae and adult beetles.