Summary: Universal Basic Income (UBI) has been advanced to deal with a number of challenges. Seldom have trials of UBI been designed adequately to measure its impact on the health of participants across the spectrum of socioeconomic status. But the data that does exist suggests that policy has the potential to improve this aspect of people’s lives. Two theoretical frames have been advanced to explain this effect. The first is based, broadly, on its impact on behaviour, highlighting the ways in which present socio-economic conditions, including needs and means-based welfare systems, disincentivise healthy choices and activity. The second is based, broadly, on its impact on the endocrine system, holding that UBI serves to protect individuals from a range of stress-related illnesses induced by socio-economic conditions associated with hierarchy and inequality. While the absence of epidemiological input into designing trials means that these frames have yet to be tested, there are good sources of data from non-UBI-related studies that support their validity. This account lays out pathways to impact, demonstrates important points of consideration in the designing of trials and argues strongly for a trial on the basis of a transformative ‘upstream intervention’ capable of shaping the way that we deal with health. In that respect, we argue that, seven decades on from the creation of the NHS, UBI can be Labour’s next great and common-sense contribution to Britain’s health.