How worried was Britain about invasion 1940-41?

Transcript
Extract from a report on Operation Dynamo, dated 3rd May 1941, concerning the evacuation of British and French troops from Dunkirk in May-June 1940

Catalogue ref: WO 106/1618

WAR OFFICE ON DUNKIRK EVACUATION

Up to 30th May, 1940, the arrangement was that British troops were to be taken off in British ships and French troops in French ships. Notwithstanding this arrangement up to noon 31st May 14,811 French troops in addition to 149,342 British had arrived in this country in British ships. The number taken off in French ships is not known but the Admiralty had the impression that the French navy made very little effort and that no effective steps had been taken to collect French coastal shipping.

On the night 30/31 May Lord Gort received orders that equal numbers of French and British troops were to be taken off in British ships. It was decided that the final night of evacuation was to be 1/2 June. Evacuation by daylight was no longer possible as the only channel was covered by enemy guns and his air action was incessant. On the morning 1st June alone we lost six ships by enemy bombing.

Notwithstanding the former decision the evacuation was continued up to and including the night 3/4June. Major General Alexander and the last of the British troops left Dunkirk in the early morning of 3rd June. This withdrawal was made in full agreement with Admiral Abrial who said he had sufficient French troops to hold the perimeter and asked only for British air and naval assistance during night 3/4 June. At considerable risk to our shipping this assistance was given.

During the period after the decision to take off equal numbers of French and British troops the numbers brought off in British ships were

British 74,943
French 97,735

The total numbers including wounded during the whole period of evacuation were

British 224,585
French 112,546

The two main reasons for the disparity in total numbers are

  1. Failure of the French Navy to make an effort to assist in the evacuation
  2. Failure of the French High command to issue any orders as to the evacuation
  3. French Commanders insistence that his troops were too tired to continue withdrawal to the coast, had resulted in their failure to reach Dunkirk while evacuation was still possible.

The War Office.
3rd May, 1941.