Yes, this is “A Field Guide to the Butterflies of Britain and Europe” by L G Higgins and N D Riley. The color plates were made by Brian Hargreaves. Higgins-Riley (as the field guide was widely called) is something of a classic, originally published in 1970. A thoroughly revised and somewhat expanded edition saw the light of day in 1980.
The guide was considered indispensable by more experienced butterfly aficionados, while being extremely difficult to use for newbies. Indeed, I wonder if Higgins-Riley isn't really geared towards actual butterfly collectors, rather than the occasional butterfly-watcher, since the plates show “pinned” specimens. Originally, Higgins also wanted to include pencil drawings of genitalia and other diagnostic characteristics hardly visible on a sunny summer day in the field!
The guide covers Europe outside the Soviet Union (almost – for some reason, it does cover the three Baltic republics) and the northern parts of Morocco, Algeria and Tunisia. It also covers the Canary Islands, the Azores and Madeira. It doesn't include species or subspecies endemic on Cyprus or the Aegean Islands. I'm not sure if this geographic range makes any kind of sense, or whether it was chosen for purely practical reasons. The Cold War? We are also kindly informed that all species are illustrated, except Delattin's Grayling and Cretan Grayling. The migratory Monarch, which occasionally shows itself in Europe, isn't covered at all, but then, it's hard to confuse with anything else!
Otherwise, I must say that the vernacular names of butterflies are more boring than those of moths, perchance suggesting that Victorian-era moth collectors were quite the characters. The butterflies, by contrast, mostly have names such as Greenish Black-tip, Lesser Clouded Yellow, Large White or Common Blue. Sounds like the name of backbenchers in the House of Lords…
OK, I admit. I'm just an occasional butterfly-watcher, not a collector. I'm also a republican. With a lower-case r, I hasten to add.