140 Mr S. M. Bruce, High Commissioner in London, to Mr R. G. Menzies, Prime Minister
Cablegram 237 LONDON, 12 April 1940, 4.07 p.m.
MOST SECRET FOR THE PRIME MINISTER HIMSELF
Present position appears that the Germans have established themselves at Oslo, Stavanger-the importance of which is valuable aerodrome-Bergen, Trondheim and Narvik, with naval losses in the open seas and Norwegian harbours indicated in Churchill's speech.
 Heavy losses of transport and supply ships have been inflicted by submarines in the Kattegat and Skagerrak, precise details of which not yet available. The Norwegians still resisting and Allied diplomatic and military missions including Admiral Evans now in Norway to encourage the maintenance of resistance.
Following is my personal appreciation of the position. The period that Norwegian resistance can be maintained and linking of southern German forces with forces at Trondheim, Bergen et cetera prevented depends on (a) the rate of flow of reinforcements and supplies via Oslo; and (b) assistance the Allies can afford to the Norwegians.
With regard to (a) heavy toll can be taken by submarine and air action but these not sufficient to stop the flow. Surface vessels which could be completely effective by blocking the entrance to Oslo Fjord unable to operate owing to narrowness of the waters and proximity to German air bases.
With regard to (b) recapture of seized ports not considered practicable by naval attack followed by landing. Recapture should quite satisfactorily be possible by landing at other points and attacking from landward side in co-operation with the Norwegians.
Action of this character to be effective must be immediate in order to anticipate linking of isolated German forces with the main body.
If Trondheim and Bergen recaptured they would constitute bases for future operations to serious embarrassment of the Germans. If these points consolidated with main German forces recapture would appear impracticable and they would constitute points of serious embarrassment to the Allies.
Narvik in my view not so urgent as the Germans cannot reinforce or consolidate with their forces there and action in southern area should have precedence.
Above is the position as I see it and which I have put to individual members of the War Cabinet.  Present decision however is to postpone action in the south pending liquidation of Narvik position which is being undertaken.