Why does the British court want to destroy a house?

Because it went against planning permission. He built it on greenbelt land, which is supposed to be protected from idiots ruining the landcsape by building ugly mock castles mixed with a tudor house. Also, if we're talking about the same case, he deliberately concealed it behind hay bales, showing that he was aware that he was breaking the law and should have been prepared that 4 years later when the hay came down it would be demolished.