British soldiers joined a major exercise on Nato’s snowy border with Russia as Finnish troops prepare to defend their country if their neighbour invades.

Around 50 men from the 3 Rifles, based in Edinburgh, spent six weeks training in the Arctic north of Finland, where they honed their survival skills in temperatures as low as minus 28C.

The C Company soldiers, who have previously had hot weather training in Kenya and Morocco, learned how to cope with icy immersion in water and how to avoid frostbite, and practised fighting in the snow and shooting while skiing.

They then joined the 3,000 conscripts, reservists and regulars from the Finnish Army’s Kainuu Brigade on Operation Northern Ax, in the forests of Vuosanka, around 20 miles from Russia and 400 miles north of Helsinki.

The British reconnaissance specialists carried out operations alongside the Finns on a wide-ranging and sophisticated simulated battle which lasted for five days and nights.

The operation was designed to test their defence, delaying, night combat and attack tactics, with commanders following the troops’ movement in real time to monitor their performance.

After years of neutrality, Finland joined Nato in 2023, extending the alliance’s northern border with Russia by more than 800 miles.

War in Ukraine and what the Russian military could do next has raised concerns in Finland – which only gained independence from its neighbour in 1917 and which last fought off invaders from the east in the Winter War of 1939-40.

Finland has mandatory conscription for men who then remain as reservists until the age of 50, meaning a population of 5.5 million could raise an army of 900,000 if they came under attack.

Reservists are called up for refresher courses and conscription has popular support across different age groups.

The British contingent were impressed with the cold-weather skills of their hosts and were aware of how seriously the Finns were preparing.

Major Henry Wootton, leading the company, said: “It is really impressive to see a country that is orientated for defence.

“They have a set-in-stone defence plan and everyone contributes to that with their conscript service when they are 18.”

Describing many Finns as “outdoorsmen and women”, Major Wootton said his men had learned from their hosts on adapting to the conditions, even if they were less experienced when it came to soldiering.

He added: “Clearly as a professional army, we have had more time to practice but we also come on the back foot because we don’t know the country and the environment as well as them.”

Rifleman Aaron Hunter, 21, from Wakefield, West Yorkshire, said the threat of a Russian invasion was one of the main reasons for training in Finland.

He said: “It’s a big talking point for the Finns and they think it’s a very high-level threat that could be around the corner – who knows?”