When twins Georgia and Melissa Laurie set off a once-in-lifetime adventure to Mexico in 2021, they thought it would be an opportunity for some sisterly bonding. Whilst on their travels, they went for an ill-fated swim in a lagoon – and found themselves in a terrifying fight for survival.

They tell their incredible story to Dr Sian Williams, and explain how in that moment, and over the years that followed, their love for each other kept them alive.