IWM caption : Supermarine Spitfire Mark IXs of No. 73 Squadron RAF, each loaded with two 250-lb GP bombs, taxy to the runway at Prkos, Yugoslavia, for a sortie against retreating German troops and supply lines. They are being watched, in the foreground, by a Bofors gun crew of No. 2914 LAA Squadron RAF Regiment, which provided the anti-aircraft defence for the airfield.