British atomic strikes could halt the 1940 campaign

What if Britain developed atomic weapons in the early 1930s and used them against Germany and Italy during the fall of France?

The 1940 campaign could end abruptly under British nuclear coercion, while other powers race to build bombs and reconsider their alliances and war plans.

A secret nuclear programme begun in the early 1930s would also require a bomber programme capable of carrying the weapons to distant targets. Proposed targets include the Ruhr, Italy's industrial triangle and naval bases such as Kiel or Taranto. Nuclear attacks during the fall of France could force withdrawals and disarmament, preserve the Allied position in Norway and perhaps prevent France's defeat. Bases retained in southern Norway would extend the threat to Germany. The United States and Soviet Union would intensify bomb research, and the Soviet Union might withdraw from Poland under British pressure. Japan might try to avoid war with Britain while attacking the United States and the Netherlands earlier, before an American bomb became available. These outcomes depend on the targets, British demands and the speed at which Axis governments accepted the new situation.