This thesis reports on a critical discourse analysis (CDA) of the SEL policy makers' conversations taking place in England and Wales during the New Labour period. The research sets out to offer a critical explanation of Welsh and English SEL policy thinking and doing and how the SEL policy discourse worked to privilege certain ideas and topics and speakers and exclude others. Thinking with theory and building on the work of Apple (2007) and Ball (2012) I draw on the contemporary tenets of critical theory to examine the (dominant) English and (often subjugated) Welsh discourse(s) to historically locate and contextualise the mainstream SEL literature within the ideological discourse of neoliberalism (Harvey, 2005). This neoliberalism is one which unequivocally drives policy in the direction of markets and propounds a thorough marketization of educational provisions and practices (Lynch, 2006).Drawing on data from a series of eight semi structured interviews with key national level policymakers, alongside documentary analysis, I argue that New Labour in England, particularly in its second term, through a particular policy network and the SEAL programme, adopted SEL as a tool of managerialism designed to shape and govern a self-managing, entrepreneurial, placid subject in the service of the neoliberal economic model. Alternatively I contend that the Welsh assembly adopted SEL as a practical and progressive tool for developing a more equal society and a more egalitarian and democratic modus operandi of social justice (rooted in normative precepts of the collective and of community cohesion). This "Welsh" approach was powerfully intertwined with the devolution programme and notions of the child as a democratic citizen with agency and rights. In both England and Wales this understanding and application of SEL was intimately connected with national identity and notions of nationhood.This work was undertaken using a CDA approach. It employed Fairclough's Three Dimensional Model (1992) of Critical Discourse Analysis and engaged with the subject and data through the three lenses of text (the written and spoken word), discursive practice (the production, distribution and consumption of the text) and social practice (the wider social, political and economic forces shaping the discourse). By illuminating through CDA the ideologically infused discursive claims to truth and value, which underpinned the rhetoric and substance of the UK (Anglo-centric) Government's version of SEL in schools and that of the devolved Welsh Government, my findings reveal the broader scale ideas and political-ontological truth claims which drove the development of SEL across England and Wales during the New Labour period; the research therein unveils the implicit but reified notions of childhood and children's wellbeing which were central to SEL development at both the national and devolved levels; it identifies the unspoken and latent ideological projects which were core to the production of divergent SEL discourses in each of the countries; and finally, it reveals the influence which national tradition, domestic power structures, cross-societal inequities and the subjugation of certain identities have had on the conceptualisation and practical delivery of SEL in England and Wales. The study concludes that the relationship between language and political ideology in England and Wales during the New Labour years powerfully shaped the SEL policy discourse. In England the result of this was a thin version of SEL co-opted into the service of the neoliberal marketplace. In Wales a similar outcome occurred but only after a very different contextualised and transformative version of SEL was relinquished due to the invasive neoliberal forces attacking Welsh education.