As part of Operation Overlord the British 6th Airborne Division was to be airlanded on the eastern flank of the landing area, around the River Orne and to the east of the town of Caen. The purpose these landings was to hold the left flank of the landing area, especially key bridges, preventing German armour from 'rolling up' the beaches from one end. The operation was to be divided into three parts.
In Operation Coup-de-Main advance elements of the division would be landed by glider and parachute during the night of the 5th/6th June. The task of these units was so seize or destroy key bridges and hold until relieved by the main forces. The main assault, codenamed Operation Tonga comprised the major part of the division, also landed by glider. These units would relieve and reinforce the initial attack. Later in the day Operation Mallard would reinforce the assault units once again, this time flying in Tetrarch light tanks and heavy weapons. This reinforcement mission came just as the German 21st Panzer division was launching a counter-attack on a vulnerable point on the invasion beaches. The appearance of troop-carrying gliders over their heads was intrumental in persuading the Panzers that they might be cut off, and they withdrew.
The operations were highly successful, and the units succeeded in taking and holding the key bridges. The fight for one such bridge over the Orne became one of the best known incidents of the invasion. It was portrayed in the film The Longest Day and the bridge was renamed Pegasus Bridge after the Airborne troops' badge. The bridge, which was replaced by a more modern one, can be found in the Pegasus Bridge museum and memorial, next to the original battle site.
See also: Operation Chicago and Operation Detroit, the American parachute landings.