Austerity measures adopted by State Parties since 2008 had a detrimental impact on social housing and welfare, deteriorating the enjoyment of the rights to housing and social security under the International Covenant on Economic, Social and Cultural Rights. The doctrine of non-retrogression – the obligation prohibiting State Parties from taking backwards steps in the enjoyment of Covenant rights – holds immense potential in holding State Parties accountable for adopting austerity measures which deteriorate the enjoyment of Covenants rights. The thesis attempts to categorise the use of austerity measures by the United Kingdom and Ireland as contrary to the doctrine of non-retrogression under the Covenant in relation to the enjoyment of the rights to adequate housing and social security. To achieve this, a two-pronged assessment of deliberately retrogressive measures is carried out: first, the State Party intention in adopting austerity measures is examined; second, a normative and empirical assessment of the doctrine of non-retrogression is conducted in relation to social housing and welfare legislation and policies adopted by the United Kingdom and Ireland from 2008 to 2021. The thesis is interdisciplinary in its approach. First, both the doctrine of non retrogression and austerity are unpacked, relying upon the disciplines of law, political philosophy and political economy to establish an overall framework to analyse deliberately retrogressive measures. Second, a doctrinal analysis of the rights to adequate housing and social security is undertaken to tailor a criterion for determining retrogression specifically for these rights. Third, a qualitative socio-legal analysis of British and Irish parliamentary budget debates is conducted to gauge whether the measures adopted by the State Parties were intended to be deliberately retrogressive. Finally, British and Irish social housing and welfare policies and legislation adopted from 2008 to 2021 are assessed from a normative and empirical perspective to determine whether they are deliberately retrogressive.