When did intervention against German rearmament become practical?

When could Britain and France realistically have intervened against German rearmament?

Around 1937 or 1938 at the earliest, and even then from a poor military position after years of underfunding.

Polish proposals for intervention while Germany was rearming ran into the poor condition of the Western powers. Treaty limits mattered to navies, while armies and air forces had also been starved of equipment and funding. Britain and France retained larger institutional bases from which to rebuild, but that rebuilding was only beginning during the 1930s. The earliest plausibly practical intervention is placed around 1937 or 1938, and even then the military position was poor.