This theoretical chapter examines how caste, colonialism, and migration intersect to shape the psychosocial realities of South Asians in the UK, foregrounding the psychological effects of these forces within bioecological and multigenerational systems. Drawing on intersectional feminism and postcolonial theory, it reconceptualises caste not merely as a social hierarchy but as an internalised structure of feeling, one that is transmitted through familial, communal, and institutional channels. The chapter explores how caste-based positions become psychologically embedded; privileged caste individuals may unconsciously absorb superiority, entitlement, and emotional detachment, while those from marginalised castes often internalise inferiority, shame, and a persistent sense of unworthiness. These embodied hierarchies fragment intragroup relations and contribute to unequal outcomes across caste lines. Set against the backdrop of postcolonial Britain, where multiculturalism coexists with racialised exclusion, the chapter shows how inherited caste schemas are reconfigured under the pressures of migration, racialisation, and acculturation. These dynamics contribute to complex identity negotiations, affective dissonance, and psychological distress, often masked by silence or misunderstood within mainstream clinical paradigms. The chapter calls for decolonial approaches to mental health and education that recognise caste as both a structural and a psychological force, advocating for intra-community reckoning and culturally grounded therapeutic interventions, research methods, and psychological frameworks to directly address caste-based trauma. In doing so, it outlines a path towards intergenerational healing, solidarity, and the dismantling of internalised oppression within diasporic South Asian communities.