A TOP secret dossier that offers a detailed and chilling account of the German version of the D-Day landings has been uncovered...and states Brighton as the main target.

The volume was compiled by the British from documents recovered from German naval archives after the war that outlined the Nazi invasion of the UK.

And the blueprint for Operation Sealion that was to have taken place in September 1940 is remarkably similar to Operation Overlord, the Allied invasion of Normandy, four years later.

Adolf Hitler identified five different sectors of the English coast to attack; from Ramsgate in Kent in the east to Selsey Bill in West Sussex in the west.

The plan was to land 100,000 German troops, 650 tanks and 4,500 horses in the first wave of the “exceptionally bold and daring attack”.

A further 500,000 soldiers would then have landed once a bridgehead had been established and fought their way inland.

The cocksure Germans were confident that such an onslaught would have led to the “rapid abandonment” of the British defences south of London.

Their first operational objective was to occupy a huge swathe of south east England, from the mouth of the River Thames down to Southampton, 14 days after the invasion.

Brighton was earmarked to be the main landing area for transport ships bringing in more troops, armour and supplies during the occupation.

And just like the Allied invasion of Normandy, the Germans would have attempted to fool the British into believing the main landings were to take place elsewhere.

A diversionary attack was planned for two days before D-Day between Aberdeen and Newcastle on the North East coast.

Hitler believed Operation Sealion would have led to a “rapid conclusion” of the war.

But crucially the invasion was entirely dependent on the Luftwaffe gaining air superiority over the British by the middle of September.

In the event the RAF won the Battle of Britain between July and October 1940, scuppering Operation Sealion.

Copies of the hard bound book called “German Plans for the Invasion of England in 1940” were only given in limited number to senior officials in the British intelligence community in 1947.

Now an extremely rare copy has emerged for sale for £5,000 with auctioneers Henry Aldridge and Son of Devizes, Wiltshire, having been owned by a collector of military for many years.

Auctioneer Andrew Aldridge said: “This is a fascinating account that was compiled just after the war by the Admiralty and was based on documents taken from German naval archives.

“This is the ‘what if’ scenario and chronicles in great detail the events that ultimately proved to be the cancellation of the invasion of England.

The account varies from exaggerated hopes of German victory to pessimistic forecasts.

“Operation Sealion was postponed until January 1941, again in May 1941 and then shelved indefinitely.

“These books were only given to a select group of people such as the First Sea Lord and the Lord of the Admiralty at the time.”

The German archives identified the ports of Le Havre, Cherbourg, Boulogne and Ostend from where they would have launched their invasion and “powerful artillery” directed at mainland Britain would have been launched from ships in the Dover Straits.

The coastal sectors the first wave of 100,000 German troops would have invaded were between Ramsgate to Deal, a 14 mile stretch from Folkestone to Dungeness, an 11 mile stretch from Dungeness to Rye, an 11 mile stretch between Bexhill and Beachy Head and then a 21 mile stretch from Brighton to Selsey Bill.

Hastings and the Isle of Wight were ruled out as they were heavily fortified.

The Germans put the British defences at 320,000 men, with machine gun nests positioned 300 yards from the coastline, artillery guns 1,000 yards inland and another line of artillery and machine gun nests 3,000 yards back.

A line of more than 600 armoured cars and tanks were said to have been positioned two miles inland and a reserve of 50,000 men a further two miles back.