The stability of Antarctic ice sheets and their potential contribution to sea level under projected future warming remains highly uncertain. The Last Interglacial (135 000–116 000 years ago) provides a potential analogue, with global temperatures 2 °C higher and rates of sea‐level rise >5.6 m ka −1 , leading to sea levels 6.6–9.4 m higher than present. The source(s) of this sea‐level rise remain fiercely debated. Here we repor...