Poor diets are the major cause of death and disease globally, driving high levels of obesity and noncommunicable diseases. Cheap, heavily marketed, ultra-processed, energy-dense and nutrient-poor food and drinks that are high in fat, sugar and salt play a major role. The high-sugar content of these products leads to consumption levels much higher than recommended. The World Health Organization recommends that sugar intake should be reduced to just 5% of energy intake by using fiscal policies and food and drink reformulation strategies. Over the previous decade, the government of the United Kingdom of Great Britain and Northern Ireland has implemented several policies aimed at reducing sugar intake. We compare the soft drinks industry levy and the sugar reduction programme, examining how differences in policy design and process may have influenced the outcomes. Success has been mixed: the mandatory levy achieved a reduction in total sugar sales of 34.3%, and the voluntary reduction programme only achieved a 3.5% reduction in sugar levels of key contributors to sugar intake (despite a target of 20%). Both policies can be improved to enhance their impact, for example, by increasing the levy and reducing the sugar content threshold in the soft drinks industry levy, and by setting more stringent subcategory specific targets in the sugar reduction programme. We also recommend that policy-makers should consider applying a similar levy to other discretionary products that are key contributors to sugar intake. Both approaches provide valuable learnings for future policy in the United Kingdom and globally