English: Two of the gun turrets of the Battle of Britain Memorial Flight Lancaster B1 bomber (PA474). The aircraft is waiting to display at Kemble Battle of Britain Weekend 2009, Cotswold Airport, Gloucestershire, England. The BBMF brochure for 2009 says “one of 7,377 Lancasters built. In the markings of No 550 squadron on one side (BQ-B) and No 100 squadron on the other (HW-R). Built in Chester, England, in mid-1945, too late to take part in World War 2.” The turret on the far left of the picture is the “tail” or “rear” position and the turret above the big red letter B is the “mid-upper” or “dorsal” position.