Back in May, while cutting back an overgrown lilac bush I found an odd little caterpillar which I identified as Common Emerald. I put it into a tub with some lilac cuttings and although it didn't seem to grow much, on 21 June, I found a small pupa on the underside of one of the leaves. The moth emerged tonight and has been released to do what it needs to do. Success.
It should be noted that this is a brand new moth for me - I may have found the caterpillar but I had never seen an adult moth until tonight.