Although this story is about the destruction of a house, it is also about the destruction of the way that life has been previously. Drastic changes are afoot in Britain, starting with the class system. Before World War Two changed both the geographical and social landscape, England's social hierarchy was almost written in stone. Rules that governed social interaction were extremely rigid. Upper class people were superior and inherited their class from their ancestors. They may or may not be wealthy - money was not an indicator of class. The inherited nature of your position in society made it almost impossible for the lower classes to climb the social ladder and move between classes. At the time in which the story is set, in a time of social unrest and change, the fortunes of many upper and upper-middle class families have been reduced, and there is unprecedented mobility among the lower classes.
Although the boys in the Wormsley Common Gang don't remember what life was like before the war (Blackie claims to have been kept awake by bombing raids but the other boys know perfectly well that he would have been one year old and asleep in a makeshift bomb shelter on the London underground) and therefore did not experience this class system for themselves, they are poised to rail against outdated assumptions that the upper class are superior. An example of this is Trevor, whose family suffered a downturn in their fortunes and therefore had to move to a far less well to do working class neighborhood. Trevor's mother still feels superior to her new neighbors, and his father, once an architect, tries to teach Trevor to value the beauty in architecture and physical things. When Trevor plans to destroy Mr Thomas' house he is really destroying everything that he believes represents his father, and the priorities that his father has.
The old social order and the desire for a more meritocratic society is reflected in the gang. When Trevor joins the gang, the boys know that his name is one that is given either to upper class boys, or upper middle class boys whose parents have aspirations of upward mobility. They shorten his name to T so that they don't undermine him, and when they want to undermine him they scornfully call him by his full name again.
Another example of the boys' hatred of the old and desire to bring in the new is the house itself. Trevor's father tells him that the house is very important architecturally. It was designed by Sir Christopher Wren, who also designed St. Paul's Cathedral, as well as palaces and weekend homes for the royal family. The house becomes a symbol of everything that the boys hate. It is a throwback to before the war, to a time of class distinctions, when the best of everything when to the best of the best, and when the larger the house meant the more important the person living in it. This is a symbolic relic that the rebellious boys want to tear down.
The author seems to take the same view as the boys. He portrays the old order and rules as ridiculous, and his portrayal of Mr Thomas is actually very cruel; after all, Mr Thomas is the victim here, but he is portrayed as a man who has brought about his own downfall. Before he retired he was a construction contractor, a job that was taken by the middle classes. The house is therefore very beautiful. It has no indoor plumbing because he has no plumbing skills; plumber were working class people and the author shows this lack of practical skills as a sign of his middle class pretensions. Despite the fact that he could easily learn basic plumbing and add an inside toilet, he doesn't, preferring to stay theoretically higher class than those who would fit an indoor toilet even if it causes him inconvenience. Above all, this is a story of the author's world view; that the class system had reached obsolescence and that a necessity for a change in the order of things had come to the fore.
