How did British help plan for D-Day?

The British played a crucial role in planning for D-Day by contributing significantly to the overall strategy and logistics of the operation. They coordinated with American forces to develop the detailed plan for the Normandy invasion, known as Operation Overlord, which included intelligence gathering, securing landing sites, and deception strategies like Operation Fortitude to mislead German forces. British military leaders, including General Bernard Montgomery, were instrumental in organizing the troops and resources needed for the amphibious assault. Additionally, the British provided vital air and naval support, ensuring the success of the landings on June 6, 1944.