First ever footage of the underside of the'doomsday' Thwaites glacier has been sent back by a robotic yellow submarine dubbed Icefin. Glaciologists have likened the groundbreaking images and video to the first steps on the moon taken by Neil Armstrong in 1969. Early analysis reveals that turbulent warm waters underneath the ice sheet, which is the same size as Britain, are causing an'unstoppable retreat'. Experts have previously predicted that if Thwaites was to melt completely, it would lead to a significant increase in worldwide sea levels of around two feet (65cm). The impact on coastal communities around the world would be catastrophic.