A divided Norway would become a maritime stalemate

What kind of war would develop if Germany held southern Norway while Britain and its allies held the north?

A difficult land stalemate would be likely, but northern bases would substantially strengthen Allied maritime patrol and Arctic convoy protection.

A north-south division of Norway would probably harden into a costly land quagmire once both sides held established ports and defenses. The larger strategic payoff would come from airfields in northern Norway rather than from repeated attempts to force the mountain front. Maritime patrol aircraft could refuel and rearm across the route, greatly easing anti-submarine and anti-surface-raider coverage in Arctic waters. Even a partial Allied foothold around Narvik could matter beyond the immediate land campaign.