ObjectiveAn industry levy on sugar-sweetened beverages (SSB) was implemented in the UK in 2018. One year later, Brexit is likely to change the UK trade regime with potential implications for sugar price. We modelled the effect of potential changes in sugar price due to Brexit on SSB levy impacts upon CHD mortality and inequalities.DesignWe modelled a baseline SSB levy scenario; an SSB levy under ‘soft’ Brexit, where the UK establishes a free trading agreement with the EU; and an SSB levy under ‘hard’ Brexit, in which World Trade Organization tariffs are applied. We used the previously validated IMPACT Food Policy model and probabilistic sensitivity analysis to estimate the effect of each scenario on CHD deaths prevented or postponed and life-years gained, stratified by age, sex and socio-economic circumstance, in 2021.SettingEngland.SubjectsAdults aged 25 years or older.ResultsThe SSB levy was associated with approximately 370 (95 % uncertainty interval 220, 560) fewer CHD deaths and 4490 (2690, 6710) life-years gained in 2021. Associated reductions in CHD mortality were 4 and 8 % greater under ‘soft’ and ‘hard’ Brexit scenarios, respectively. The SSB levy was associated with approximately 110 (50, 190) fewer CHD deaths in the most deprived quintile compared with 60 (20, 100) in the most affluent, under ‘hard’ Brexit.ConclusionsOur study found the SSB levy resilient to potential effects of Brexit upon sugar price. Even under ‘hard’ Brexit, the SSB levy would yield benefits for CHD mortality and inequalities. Brexit negotiations should deliver a fiscal and regulatory environment which promotes population health.