German Air Ministry issues Orientation Book Great Britain

This contains an assessment of British air power alongside alongside details of potential British targets in the event of war. A series of ‘target files’ was created which allocated each target a code (e.g. GB10 for Airfields; GB50 for power stations; GB45 for docks; GB45 3 for Millwall Dock). The document, however, failed to recognise the extent to which British industry had moved onto a war footing after the Munich Crisis. It assessed that the British Isles presented "very difficult meteorological flying conditions".

When a thorough aerial survey of Britain had been completed, a target folder was compiled for each location comprising:

  • a 1:250,000 scale map to determine aircraft approach
  • proximity of enemy airfields
  • navigational aids such as railway lines
  • a 1:5000 scale map of the target

Other details which might be included were:

  • the most important parts of the installation
  • the most advantageous time to attack
  • the best type of bomb for the installation

The number of British targets identified exceeded the strike capacity of the Luftwaffe bomber fleets so it was necessary to prioritise targets. In order to do so it was necessary to determine:

  • what category of goods was of most importance to the enemy’s military?
  • what level of stockpiling existed?
  • the means of disrupting supplies of essential materials
  • the main dockland areas
  • the main inland transport routes
  • the vulnerable points along internal transport routes
  • the location and generating capacity of power stations
  • the main electricity power supply lines

It was the job of Luftwaffe Intelligence to determine:

  • when and under what circumstances a target might be attacked to offer the best prospect of success?
  • what might be the consequences to the enemy of a successful attack?
  • how might the success of an attack be assessed?

The document makes clear the necessity for continuous reassessment of the results obtained through analysis of the surveys. In a fast-changing political and industrial landscape, it was essential to keep track of new (or diminished) sources of raw materials and development of new industrial processes and factories. With a clear directive to concentrate on the "centre of gravity" of the enemy, the manual states "operate only against the currently most important elements."