If Germany failed to invade Norway

How would a failed German invasion of Norway affect the naval war?

It would restrict German northern access, complicate U-boat operations, and alter how Arctic and Atlantic convoy routes could be protected.

A failed German invasion would leave Norway actively hostile and Sweden either hostile or firmly neutral. Germany would lose much of its ability to threaten the Arctic convoys from the north. Sea and air patrols between Scapa Flow and Norway could force U-boats to cross the North Sea submerged, restricting their access to the North Atlantic. If France still fell, more northerly Atlantic convoy routes would keep ships farther from German submarine operating areas. Mining the southern entrance to the Irish Sea is offered as another possible British response.