Caterpillars munching on a nasturtium leaf

I've stayed close to the house today as I felt a bit under the weather. Just outside the back door close to which I'm sitting are some containers we planted up just before I had my operation. They are doing wonderfully well, with lots of growth and flowers. My main interest is in the morning glory plants I grew from seed. I hope they will flower for the first time this coming week.

I've watched many cabbage white butterflies visiting those plants. Yesterday I found a collection of many tiny caterpillars on the underside of a nasturtium leaf.

Today on the top side were these two large caterpillars. I turned the leaf over and saw the small caterpillars are still where they'd hatched, immediately below where these two are munching. There could be a disastrous destruction of their habitat. I shall watch this space.