The English Channel first developed as an arm of the Atlantic Ocean during the Pliocene period, which spanned from 5.3 to 2.6 million years ago. This formation resulted from differential tectonic uplift along pre-existing weaknesses in the Earth's crust. During this early era, Britain and Ireland remained part of continental Europe, linked by an unbroken ridge known as the Weald, Artois anticline. The ridge ran between the Dover and Calais regions and acted as a natural dam holding back a large freshwater pro-glacial lake. This lake existed in the Doggerland region, now submerged under the North Sea. Meltwater from the Baltic and ice sheets from Caledonia and Scandinavia fed the lake while blocking its exit. The sea level was about 100 meters lower than it is today.
Between 450,000 and 180,000 years ago, at least two catastrophic glacial lake outburst floods breached the Weald, Artois anticline. These events contributed to creating some of the deepest parts of the channel such as Hurd's Deep. The first flood occurred 450,000 years ago and would have lasted for several months. It released as much as one million cubic metres of water per second. The flow started with large but localised waterfalls over the ridge which excavated depressions now known as the Fosses Dangeard. The flow eroded the retaining ridge causing the rock dam to fail and releasing lake water into the Atlantic. After multiple episodes of changing sea levels during which the Fosses Dangeard were largely infilled by various layers of sediment, another catastrophic flood some 180,000 years ago carved a large bedrock-floored valley called the Lobourg Channel. This valley was some 500 meters wide and 25 meters deep from the southern North Sea basin through the centre of the Straits of Dover and into the English Channel.
Historical Invasions And Naval Wars
The most significant failed invasion threats came when the Dutch and Belgian ports were held by a major continental power. Examples include the Spanish Armada in 1588, Napoleon during the Napoleonic Wars, and Nazi Germany during World War II. Successful invasions include the Roman conquest of Britain, the Norman Conquest in 1066, and the Glorious Revolution of 1688. The concentration of excellent harbours on Britain's south coast made possible the largest amphibious invasion in history, the Normandy Landings in 1944. Channel naval battles include the Battle of the Downs in 1639, the Battle of Dover in 1652, the Battle of Portland in 1653, and the Battle of La Hougue in 1692.
From the reign of Elizabeth I, English foreign policy concentrated on preventing invasion across the Channel by ensuring no major European power controlled potential Dutch and Flemish invasion ports. Her climb to pre-eminent sea power began in 1588 as the attempted invasion of the Spanish Armada was defeated. This defeat resulted from outstanding naval tactics by the English and Dutch under command of Charles Howard, 1st Earl of Nottingham with Sir Francis Drake second in command. Stormy weather also played a role in the outcome. Over the centuries the Royal Navy slowly grew to be the most powerful in the world. During the Seven Years' War, France attempted to launch an invasion of Britain but was thwarted following the British naval victory at the Battle of Quiberon Bay in 1759.