This is The Vapourer, Orgyia antiqua (Linnaeus, 1758), an unusual day-flying moth found across The British Isles but most commonly in the south. Mrs Sciencebase spotted one this time last year, just after I’d started mothing, and another this morning a year later almost to the day (2/8/18 vs 29/7/19). I managed to get a resting shot before it flitted away.
It seems to amble about on the wing with no clear direction, takes its time to head for a window, back and forth it goes. But, I did manage to get one or two decent in-flight shot out of almost 100 snaps fired off in burst mode.
The female of the species is flightless, which is more commonly a trait of winter moths, but the species is active July to September. Moreover, the female lays her eggs on her own cocoon and these then over-winter before emerging the following year as hairy larvae to feed mainly on the leaves of deciduous trees. According to the UK Moths site, this species is common over The British Isles but prefers the suburbs of Southern England. Ironic I suppose…is that where most of the ex-smokers are these days?