Here's how we do it at Morrisons. Today is 31/7, from 7pm today Produce Dept (Fruit & Veg) and Fresh Food Pre-packed (Meats, Pies, Sausages, Bacon, Yoghurts, etc) will go round, remove all items dated 1/8, reduce them by some 25% and place them in the Reduced Section.
Tomorrow those items that still remain unsold will be further reduced down to 25% of original price - that usually gets rid of them to the '19p Brigade' as we call them.
(Butchery does first reduction for 1/8 at approx noon on the 1/8 and final reduction as other departments).
PS I don't call any customer 'Darlin' - well at least not to their face ;))
I thought all other Supermarkets followed a similar procedure.