OBJECTIVE: The UK Soft Drinks Industry Levy (SDIL) (announced in March 2016; implemented in April 2018) aims to incentivise reformulation of soft drinks to reduce added sugar levels. The SDIL has been applauded as a policy success, and it has survived calls from parliamentarians for it to be repealed. We aimed to explore parliamentary reaction to the SDIL following its announcement until two years post-implementation in order to understand how health policy can become established and resilient to opposition. DESIGN: Searches of Hansard for parliamentary debate transcripts that discussed the SDIL retrieved 186 transcripts, with 160 included after screening. Five stages of Applied Thematic Analysis were conducted: familiarisation and creation of initial codebooks; independent second coding; codebook finalisation through team consensus; final coding of the dataset to the complete codebook; and theme finalisation through team consensus. SETTING: The United Kingdom Parliament. PARTICIPANTS: N/A. RESULTS: Between the announcement (16/03/2016) - royal assent (26/04/2017), two themes were identified 1: SDIL welcomed cross-party 2: SDIL a good start but not enough. Between royal assent - implementation (5/04/2018), one theme was identified 3: The SDIL worked - what next? The final theme identified from implementation until 16/03/2020 was 4: Moving on from the SDIL. CONCLUSIONS: After the announcement, the SDIL had cross-party support and was recognised to have encouraged reformulation prior to implementation. Lessons for governments indicate that the combination of cross-party support and a policy's documented success in achieving its aim can help cement the resilience of it to opposition and threats of repeal.