This research examines the impact of recent and anticipated changes in free school meal eligibility on state-funded mainstream schools in England. In particular, our research focuses on the extent to which both the pandemic and transitional arrangements introduced to smooth the roll out of Universal Credit are affecting free school meal eligibility. It also explores the implications for both the measurement of the attainment gap and for how government funding for schools is being targeted towards pupils from more disadvantaged backgrounds. Key Findings: (1) Our research demonstrates that the transitional arrangements introduced by the Government to smooth the roll out of Universal Credit are significantly increasing the number of free school meals eligible pupils; (2) The COVID-19 pandemic has amplified this trend, with the number of free school meal eligible pupils increasing by almost 300,000 between January 2020 and 2021; (3) The pupils who became newly eligible for free school meals during the pandemic were disproportionately drawn from more disadvantaged areas, and from schools which were most disadvantaged before the pandemic; (4) These changes in free school meal eligibility will affect the composition of the disadvantage group. On average, newly free school meal eligible pupils have higher attainment compared to those who are already eligible, albeit lower attainment than their non-disadvantaged peers; (5) Over the coming decade, it will become increasingly hard to tell whether apparent changes to the attainment gap are being driven by changes to the composition of the disadvantage group, economic conditions or genuine attainment changes; and (6) The Pupil Premium grant has not been successful at ensuring that funding for disadvantaged pupils is protected over time.