The VERY hungy caterpillar

Being a brand new house, which was a building site until earlier this year, the vicarage doesn't have much by way of a garden. The land is there, right enough, and it has been, as the estate agents would say "laid to lawn" - which is fine by me for the moment. The lovely Libby is a very keen gardener, who would undoubtedly cause havoc if I had any prized blooms to cherish...so for this year,I'm mostly content to leave things as they are.
I do, though, have quite a collection of pots, - the only gardening I allowed myself at the curate's house, since I knew we were only there for four years - so I planted those up a few months ago and have been glad of the colour they provide. I was specially pleased with some tumbling nasturtiums, which cheered up the front porch no end - or did until yesterday.
When I left the house at 1.30 they looked something like this

When I got home one hour later, the picture had changed somewhat ....
The plant was completely stripped of its leaves, - only ravaged stems remained.
Closer investigation revealed no less than 42 of these little dears gathered on one stalk


and making decidedly free with the next pot along. The neighbouring containers were similarly afflicted. I've just googled, and it seems that when they grow up these caterpillars will, predictably, turn into cabbage white butterflies...
It would have been nice if they could at least have been something exotic, but whatever else they are certainly efficient. Eric Carle knew a thing or two!