This caused the defenders to divert their forces from the fighting in Normandy, holding them in reserve for an invasion in the Pas de Calais, to the east.
The desired effect would be to force the German command to pull units from the front line and redeploy them to protect the western coast.
The plan was for two Royal Canadian Navy destroyers, Haida and Huron, to make a series of fake radio transmissions, which would be intercepted.
The beginning of the operation went smoothly, with the two ships signalling that the invasion fleet had been delayed by engine problems, and giving a revised plan.
This may have been helped by the Allied air report - the pilot would have been informed - and by a lack of any corroborating evidence; for example, there was no attempt at spoofing radar signals, as had been carried out for the main invasion by Operation Glimmer and Operation Taxable.