Relations between Norway and Sweden are being strained with the publication of a new book, which details how Stockholm aided the Nazis during WW2 as their neighbours fought and lost a decisive battle against the German invaders.

Sweden stayed neutral in the war but Norway was among the first conquests of Hitler.

Now a new book shows how Sweden let the Germans use its efficient rail network to transport men and materials to the battle of Narvik, where British troops were deployed in a bid to stave off the Nazi hordes.

Narvik-based journalist Espen Eidum spent three years sifting through Norwegian, Swedish and German archives to discover how the Nazis had managed to get troops and supplies to the front lines in Narvik in 1940, enabling them to turn a losing battle into a decisive victory that led to the conquest and brutal occupation of the whole country....