In my 15 years of teaching English to hundreds of children in various parts of England, there are four books that have been on the curriculum in every school I have found myself in, with no exception: Of Mice and Men by John Steinbeck, Animal Farm by George Orwell, An Inspector Calls by JB Priestley and Private Peaceful by Michael Morpurgo.
They have each been well-known classics and perennial favourites for decades. But if you somehow managed to skip them, here's a quick summary. Of Mice and Men: depression-era friendship strained by a world of toxic masculinity. Animal Farm: a political warning where the farm becomes an allegory for the Russian revolution. An Inspector Calls: an upper-class British family wrestles with basic morality when a working-class woman is announced dead. Private Peaceful: two brothers leave the rural idyll to face the horrors of the frontline in the first world war.