A British Iceland and the opening of the Atlantic war

What if Britain had taken Iceland during the Napoleonic Wars and retained it into the twentieth century?

Britain would likely enter World War II with established Icelandic bases and patrol aircraft, improving early Atlantic surveillance and pressure on German raiders.

This counterfactual imagines Iceland evolving into a self-governing dominion with permanent British basing rather than requiring wartime occupation. Existing airfields and Coastal Command patrols would give the Allies an immediate North Atlantic search network. That could increase the chance of locating German surface raiders such as Deutschland early in the war. Peacetime political control and basing arrangements can determine how quickly maritime surveillance becomes effective in a crisis.