http://www.onwar.com/chrono/1939/sep39/f20sep39.htm
RAF meets Luftwaffe in battle
Wednesday, September 20, 1939
On the Western Front... For the first time, RAF and Luftwaffe aircraft engage when a flight of German Me109 fighters attack 3 Fairey Battle reconnaissance bombers over the Siegfried Line, over Aachen; 1 Me109 and 2 Battles are shot down.
From London... Britain and France vow to keep fighting in response to recent peace offerings by Hitler. They declare that the Allies “will not permit a Hitler victory to condemn the world to slavery and to ruin all moral values and destroy liberty.” Meanwhile, the British Conservative Party government, under the leadership of Neville Chamberlain, is denounced by the Labour Party opposition, in the House of Commons, for failing to help Poland enough against the German and Soviet invaders.
Labour was still pro-war, even after the Soviet Nazi alliance, interesting.
"destroy liberty"?
It happened anyway.