More than a thousand Royal Marines have started their largest deployment to the Arctic for "many years", the Royal Navy has said.
Troops from 30, 45 and 47 Commando are all in northern Norway for their annual cold weather training programme.
The deployment is an increase by at least 200 personnel on last year.
It is in preparation for a large-scale exercise that's being held by Norway in late February, the Royal Navy said.
45 Commando - 3 Commando Brigade's high readiness unit - have been put through their paces 200 miles inside the Arctic Circle, where temperatures plummet as low as -30°C.
Personnel must take on survival training before learning to move and fight across one of the world's toughest terrain.
"Overcoming this demanding environment presents its own challenges," said Lieutenant Alex Saunders, from 45 Commando.
"The survival phase of training includes learning how to construct snow shelters, navigating by the stars and how to trap animals in a survival situation."
The Cold Weather Warfare Course has three phases – survival, mobility and warfare - and culminates in a final exercise that puts the newly-taught skills into practice.
In late February, 45 Commando will take part in Exercise Cold Response along Norway's coastline.
The exercise, that is described as "large-scale, multinational war games", will see the Marines practise their amphibious capability.
45 Commando will operate from different ships alongside NATO partners and allies.
The Marines are deployed to Norway until March.
Cover image: A Royal Marine takes part in an ice-breaking drill (Picture: Royal Navy).