Details of 139 Squadron from:
RAF History - Bomber Command 60th Anniversary
At the beginning of the last war it was equipped with Blenheims and flew the first RAF sortie to cross the German frontier; and it won one of the first two decorations of the war.
After duty in France (during which it suffered very heavy casualties) the squadron returned to England, re-formed, and subsequently made many attacks on fringe targets in NW Europe - including the invasion ports - and many anti-shipping sweeps.
First Operational Mission in WWII: - 3rd September 1939 : Photo reconnaissance of Wilhelmshaven and airfields in NW Germany by one Blenheim.
First Bombing Mission in WWII: - 12th May 1940 : 9 Blenheims dive-bombed German troops advancing along the Maastricht- Tongres road. The formation was subsequently attacked by enemy fighters and only 2 a/c returned. 2 of missing a/c believed shot down in flames. 2 crews later rejoined sqdn after having forced-landed near enemy lines.