Last year water temperatures in the North Sea reached record levels, with average surface temperatures a balmy 11.6C, the warmest since measurements started in 1969. And as waters continue to warm, a new study suggests great white sharks could start prowling British waters.

Olivier Lambert, from the Royal Belgian Institute of Natural Sciences, and colleagues studied whale fossils recovered from North Sea sediments dated to around 5m years ago. North Sea waters were warmer at this time and were home to several species of whale and shark. Fossilised tooth fragments embedded in the whale skulls revealed that sharks had feasted on them.

The findings, published in Acta Palaeontologica Polonica, show that one tooth belonged to a bluntnose sixgill shark (common in Mediterranean waters today) and the other to the extinct mako shark cosmopolitodus hastalis, a relative of today’s great white shark.

This fossil evidence provides a hint of how ecosystems may change as climate breakdown warms our seas. Today’s North Sea is too shallow to support modern-day whales, but increasing numbers of dolphins and seals are being attracted to the warming waters. Lambert and his colleagues postulate that this, in turn, could attract great white sharks and other large marine predators back to UK seas.