What saved many british and french forces from the germans in 1940?

Weather conditions and good discipline

Explanation:

During 1940 Germans were prevailing. They conquered the Benelux countries and their next goal was France. On May 26th the German troops started pressuring the British and French army near the beach of Dunkirk. More than 300 000 soldiers were entrapped by the Germans. The Germans had around 800 000 soldiers, so it looked that the situation can't be any worse. Still, the Allies started evacuating themselves. On the first day only 7 600 soldiers left the beach of Dunkirk, but just two days later that number was higher than 40 000. At the end around 338 000 soldiers retreated, mostly because of the good discipline of the soldiers and good weather conditions, which allowed them to evacuate themselves in more than a week.