Want the best of The Telegraph direct to your email and WhatsApp? Sign up to our free twice-daily Front Page newsletter and new audio briefings. Individual houses along the coast that had been fortified and occupied by the Germans were also highlighted.The maps cover the areas of Normandy where Allied paratroopers dropped a few hours before the beach landings. Not only were roads, bridges and streams marked but even their length and width were noted.One of the maps covers ‘Dog’ section for Omaha Beach, which featured in the Steven Spielberg film Saving Private Ryan.The 1:25,000 or 2.5ins to 1 mile scale maps were colour-coded with blue for comfirmed enemy positions, purple for unconfirmed and orange for amended positions. The most up-to-date maps for the D-Day invasion have come to light 72 years later to show the incredible detail the Allies went to to ensure victory.The 24 original maps were drawn up just two weeks before the momentous operation and gave the military commanders the most contemporary reports of the state of the five Normandy beaches.The charts, marked ‘Top Secret’, were so detailed they contained almost the exact number and positions of mines, pill boxes and other defence works the Germans had laid as part of Hitler’s Atlantic Wall. One of the maps covers ‘Dog’ section for Omaha BeachCredit:Abbie Trayler-Smith for The Telegraph A man of Sword beach where British troops came ashoreCredit:C&T/BNPS The maps, that spread out to 3ft by 2.5ft, were dated May 20 when the date and location for the Allied invasion of Europe was still only known by a select few.Indeed, they were for members of the ‘BIGOT’ list only – the limited number of military top brass who knew about the plans for Operation Overlord.An instruction along the top told the holder the maps were not to be carried in operational aircraft in case it crashed behind enemy lines.The documents were the culmination of two years of work to gather intelligence and photographs of the Normandy coast.The operation involved a bogus BBC competition for British holidaymakers to send in their photographs of the French seaside and Allied divers taking panoramic snaps of the beaches under the noses of the Germans. “There are no other maps that are as up-to-date as these that we know of.”They are rare. Every now and again one might pop up from the family of a senior officer but to get so many of them in one go is quite something.”They are in very good condition.”Very few have survived and this is the largest single grouping we have seen.”The maps include Gold Beach between Colleville and Arromanche, Sword Beach between St Aubin and La Breche, ‘bloody’ Omaha Beach at St. Pierre-Du-Mont and St. Marie-Du-Mont at Utah Beach.They are being sold on September 7 and expected to fetch £2,800. The maps have emerged now after an unknown dealer bought them from a descendant of a senior military officer who was involved in Operation Overlord.They are being sold in eight separate lots by C&T Auctioneers of Ashford, Kent.Tim Harper, of C&T Auctioneers, believes the maps were kept by a senior Allied military leader after the historic operation.He said: “These were the last printed maps before D-Day.”They are incredibly detailed and gave the main military leaders vital information on the presence of defences, machine gun posts, pill boxes and trenches.”The maps are dated May 19 and D-Day was put back once or twice before it was launched on June 6, 1944.