Which British novelist is recognized for her exploration of postcolonial themes in "The God of Small Things"?

The novel "The God of Small Things" is actually written by Arundhati Roy, a prominent Indian author rather than a British novelist. However, she has gained international acclaim, making her work significant in discussions around postcolonialism. The novel delves into the intricacies of caste, family dynamics, and the impacts of colonial history in India.

Roy's narrative style and thematic focus provide a critical examination of societal issues in postcolonial contexts, making her a key figure in literature that interrogates the legacies of colonialism. The nuances in her storytelling and character development highlight the complexities of identity and belonging in a postcolonial landscape, which aligns with the exploration of postcolonial themes.

The other authors listed, while notable in their own right and contributing to discussions around colonial and postcolonial themes, do not relate directly to "The God of Small Things." Therefore, Roy's significance in this specific context makes her the correct choice for this question.