Devon based submariners have been testing their skills in some of the coldest climates in the world. Below you can see Plymouth based Royal Navy submarine HMS Trenchant breaking through the ice in the North Pole.
HMS Trenchant has been working alongside two US submarines in a training exercise making sure they can operate in the harshest conditions and beneath the ice cap.
The Royal Navy say the exercise "allows the submariners to test a range of equipment, notably sonar, against live 'targets' and to practice tracking and simulating attacks against other submarines."
The Royal Navy say that exercises like this are vital in maintaining the "operational readiness of the Royal Navy's submarine fleet and in maintaining the security of the North Atlantic and Arctic oceans."