What weakness? Briton had the largest navy in the world. Their French allies has the largest army in World and the Czech army was well trained and well equipped with excellent border defenses. If Hitler attacked Czechoslovakia in 1938, he would have been swiftly defeated. After the Czechs were stabbed in the back, the German generals were astonished by the strength of the Czech defenses.
Wiki: “Although Britain had increased military spending and funding prior to 1939 in response to the increasing strength of Nazi Germany, its forces were still weak by comparison – especially the British Army. Only the Royal Navy – at the time the largest in the world[3] – was of a greater strength than its German counterpart. The British Army only had nine divisions available for war, whereas Germany had 78 and France 86.”