Reddit reviews The Forager Handbook: A Guide to the Edible Plants of Britain

The Forager Handbook by Miles Irving is very thorough in it's number of edibles, but not fantastic to carry around or for ID. I combine it with The Wild Flower Key by Francis Rose. I pick a couple plants from the Forager Hand book at a time and look for them on a walk.
Another book is the River Cottage Hedgerow by John Right, in fact all three of his book are well done; Mushrooms and Edible Seashore.