TOP SECRET Casualties inflicted by air defences 9. If an airborne attack was launched as a complete surprise and our defences had not been alerted in any way, it is probably that very few casualties would be inflicted on the enemy in the air, either by fighters or by LAA guns. (Because of the nature of the targets which we think the U.S.S.R. would choose, only LAA guns could be brought to bear). 10. If, however, it proved possible to alert the defences seven days before the attack we think that the following results might be achieved:(a) Fighter Defences Since we have assumed that airborne operations would be undertaken in conjunction with full scale bombing raids by the Long Range Air Force, which of themselves would be capable of saturating our defences, it is impossible to give any exact figure of casualties to transport aircraft.