The attack was initiated several times in September and October that year but unreliable ships and unfavourable weather caused the plan to be aborted on each occasion.

The British Government made strenuous efforts to meet the invasion and also sought to attack the Germans before any landings took place.

As invasion barges were seen to gather in French ports along the English Channel, the Royal Air Force (RAF) was sent to attack them by bombing.

[1] Experiments by the Petroleum Warfare Department (PWD) aimed to burn the invasion barges before they could reach the English shore.

The idea of using fire ships against Hitler's invasion just as the English had attacked the Spanish Armada in 1588 appealed to Churchill's sense of history.

[5] Captain Augustus Agar was an officer of the Royal Navy, who had been awarded the Victoria Cross (VC) in 1918 was chosen to lead the operation.

[8] Another problem with secrecy was the difficulty in acquiring reliable motor-boats on which the crew would escape; there was an unwillingness to release good boats to equip ancient oilers and there was a last minute panic to get speed-boats.

To this lethal load, bundles of cordite, gun cotton and old depth charges were added to give the ships more punch.

[9] Chief Petty Officer Ronald Apps recalled, In July 1940, I joined a Royal Fleet Auxiliary tanker – the War African – that was anchored off Sheerness for an idea that I have always assumed was thought up by Churchill.

Those four weeks were a bit hairy because the tanker was full up with fuel oil when it came to us and it was primed and ready to explode and there were air raids at night.

Unwilling to sacrifice the element of surprise and under orders from Churchill not to hesitate to call things off if the plan did not go well, Agar cancelled the operation.