One from the archives taken in Cheshire in the 1980s. It shows two Large White Butterfly caterpillars on Nasturtium leaves.
I can’t explain the difference in size between the two unless they hatched from different groups of eggs. I had seen a female Large White Butterfly egg laying on the Nasturtium plant and photographed the eggs. I later photographed the eggs hatching and the tiny caterpillars exploring the leaf they hatched on. So I’d have thought that those caterpillars would be similar sizes unless they grow at different rates.