Operation Castle

Over the holidays I was watching, for the ‘nth’ time, the film ‘Heroes of Telemark’ – the classic 1965 film starring Kirk Douglas and Richard Harris. It was based on a real WW2 operation to sabotage Norwegian heavy water production, which the Nazi’s needed for atomic bomb research. It reminded me of another planned raid I came across by accident in the National Archives last year.

This was Operation Castle, a plan to destroy the hydroelectric power station at Blaafjeldit near Jossingfjord in Norway. It powered a nearby Ilmenite mine, the sole German source of the mineral. It is the most important ore of titanium, today an important strategic alloy metal, but in the 1930’s it was widely used as titanium oxide in paint, fabrics etc. The British analysis was, ‘a commodity of some importance though not of great importance to Germany’s war effort.” 

The fiord is better known as the site of the Altmark incident in February 1940 when a British destroyer freed British prisoners captured by the Graf Spee. After this Norwegian patriots became known as Jossings, in opposition to the collaborator Quislings.

Even today, the site is pretty isolated and looks little different from 1941 as this Google Map shows.

There is one road around the fiord and a deep-water wharf, which in 1941 was used by the mine and power station. No coastal defences had been identified in the intelligence summary. The nearest troops were small detachments at Anasira, 4 miles away, and Rasvag, 10 miles away. There were 300 men at Flekkefiord (15miles) and 1200-1500 at Egersund (20 miles). The nearest airfield was Stavanger, about 50 miles away. Intelligence estimated that it would take reinforcements at least an hour to arrive and the roads could be easily blocked.

The plan was to attack on 17/18^th January 1941 with 125 troops and a further 50 as a reserve. They would be landed by two destroyers, with a further destroyer covering and one submarine operating as a navigational mark.  Fighter air cover was limited to 150 miles from Scotland for the return journey. At this time of year, there were 17 hours of darkness and the operation was estimated to take three hours on the ground.

On landing, 50 troops (Group B) would go down the fiord to destroy the old power station and block the road. Another 50 plus 25 engineers (Group A) would go up the fiord to block the road and destroy the power station and dam. The 50 troop reserve (Group C) would hold the wharf and cover re-embarkation. This is the hand-drawn map in the War Office file.

The aim was to destroy the wharf, power plant and associated equipment linked to the mine, but not the mine itself. The assessment was that bombing would not achieve accurate results, and the raid could put the mine out of operation for the winter months.

The plan was approved on 2 January 1941 by the Chiefs of Staff. They argued that it would be useful raiding experience, boost Norwegian morale, interrupt road communications and damage the German war effort. It was also a low risk operation given the absence of a garrison, reliable intelligence and good local guides.

However, perhaps surprisingly, Churchill rejected the plan on 7 January. The War Cabinet minute states, “I cannot consent to this. It will only disturb the whole Norwegian coast, for reasons and objects which are trivial.”

So, it didn’t happen, but none the less an interesting scenario for wargamers. It involves small numbers of troops with German reinforcements trying to fight their way down both roads. Replicating the steep terrain might be a challenge. Where is that ModRoc when you need it?

Some 28mm British troops of the period