How worried was Britain about invasion 1940-41?

Transcript
Details of Operation Sealion, the planned German invasion of Britain, September 1940

Catalogue ref: CAB 101/347

Source a

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General Aim

"The Supreme Commander [Hitler] has ordered the services to make preparations for a forced landing in England. The aim of this attack is to eliminate the mother Country as a base for continuing the war against Germany, and, if it should be necessary, to carry out a complete occupation.

"The order to execute this operation depends on the political situation. Preparations are to be made in such a way that the operation can be carried out from 15th September.

"While continuing with its occupation duties in France and maintaining the security of the other fronts, the Army's task will be to land strong forces in Southern England, defeat the English army, and seize the capital, Other areas of England will be occupied as opportunity permits".

Source b

General Plan

"(a) The Luftwaffe will destroy the English Air Force and the armament production which supports it, and it will achieve air superiority. The Navy will provide mine-free passages and, supported by the Luftwaffe, will bar the flanks of the crossing sectors.

(b) The Army's landing forces will first win local bridgeheads [pieces of territory which can be held securely] with the specially equipped forward echelons [specially prepared invasion troops] of the nine 1st-wave divisions. Immediately afterwards, they will widen these bridgeheads into a connected landing zone, the possession of which will cover the disembarkation of the following troops and ensure early uniform control on the English shore. As soon as sufficient forces are available, an offensive will be launched towards the First Operational objective, i.e. Thames Estuary - heights south of London - Portsmouth. As the British will make counter attacks against the German troops who have landed first, and as they will resist with every means further German gains in terrain, bitter fighting is to be expected. Command and organisation of troops must be equal to the decisive significance of these initial actions.

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