This is what the pilot who dropped the atomic bomb on Hiroshima REALLY thought

At 8.15am on August 6, 1945, the Japanese port city of Hiroshima was destroyed by a single bomb dropped by an American B-29 Superfortress. This incredibly powerful new weapon – codenamed Little Boy – detonated with the equivalent of 15,000 tons of TNT sending heat and shockwaves blasting across the city.

The temperature close to the epicentre reached several thousand degrees centigrade, as hot as the surface of the sun, causing an enormous firestorm that consumed everything within a mile radius. Steel building frames liquefied, traditional Japanese wooden houses and buildings were reduced to ashes, while flying birds and animals burst into flames. Within minutes of the blast, nine out of 10 people within half a mile or less from ground zero were dead – in many cases leaving no trace but the shadows of where they had been standing or sitting down.

The first atomic bomb would eventually kill over 70,000 people instantly and hasten the end of the war against Japan. And the aircraft that delivered Little Boy was as futuristic as the weapon itself. The B-29 Superfortress was a remarkable invention. Capable of flying above 30,000 feet, its four, fuel-injected engines gave its nine-man crew a range of more than 3,000 miles, kept safe in a pressurised fuselage, with a computerised gun system that made it almost impossible for Japanese interceptors to shoot it down.

The programme to build the B-29, successor to the B-17 Flying Fortresses used in the European campaign by the USAAF Eighth Air Force, had cost the US government more than building the atomic bomb itself. The aircraft – christened Enola Gay after the mother of the man that would fly it into the history books – was so advanced and its cargo so precious that only the country’s finest pilot and crew were selected for its deadly mission.

That pilot was Colonel (later Brigadier General) Paul Tibbets Jnr, whose passion for flight began in 1927 in the rear cockpit of an old biplane at the age of 12 while waiting for take-off from a horse-racing track outside of Miami. Born in Ohio, his father had moved the family to the warmer climate of Florida where he ran a successful confectionary business. The young Tibbets’ flight in the biplane was a promotional stunt, dropping candy on parachutes to the hundreds of eager children below.

It would be the making of him, as he recalled: “I could see the unfortunate earth-bound mortals crawling around like ants on the ground below… Nothing else would satisfy me, once I was given an exhilarating sample of the life of an airman.”

Military academy would instil in Tibbets a liking for discipline, routine and the skills to lead men. With the US in the grip of the Great Depression, he yearned to fly and, with the tacit support of his mother, Enola Gay, successfully lobbied his father, who wanted him to go into medicine, to apply for the country’s new military arm, the Army Air Corps. He would graduate in February 1938 as a second lieutenant.

Within five years Tibbets had logged thousands of flying hours in the Air Corps’ newest four-engine, long-range bomber, the B-17 Flying Fortress, and been in the vanguard of the establishment of the Eighth Air Force in eastern England. Now a major, Tibbets would lead a squadron within the 97th Bombardment Group, earning a reputation as a trusted and effective combat leader. By the end of 1942, he had led the Eighth Air Force’s first 100-bomber raid and survived. The attrition rate of crews was high, morale see-sawed as he and his crews adapted their tactics to survive missions. He would then be transferred to the North African campaign.

By February 1943, as Germany suffered calamitous defeat at Stalingrad, and the Allies defeated Erwin Rommel’s Afrika Korps, America was secretly marshalling its scientific base to create the weapon it hoped might bring war to an end – the atomic bomb.

Later codenamed the Manhattan Project, this top-secret programme led by General Leslie Groves and one of the world’s brightest physicists, Professor J Robert Oppenheimer, would involve thousands of workers in plants spread across America. At the project’s heart was the scientific weapons laboratory housed in the New Mexican desert at Los Alamos.

General Groves had built the Pentagon before the war and developed the expertise to bring theories of nuclear weaponry off the drawing board to construct a weapon of mass destruction in three years. Now what he required was the right man to lead a hand-picked crew to carry out the mission in the new B-29 bomber.

Tibbets was secretly vetted by US intelligence and the FBI, then briefed by General Groves’ security team and given the job in early 1943 with the ominous warning: “Colonel, if this is successful, you’ll be a hero. But if it fails, you’ll be the biggest scapegoat ever. You may even go to prison.” Based in a remote air base in Utah, he would spend the next 18 months putting together the elite 509th Composite Group. Although Tibbets retained the rank of colonel, he was granted all-consuming authority across the United States military and governmental arms.

The codeword “Silverplate” guaranteed him anything he required for the operation. The 509th received the best 15 B-29 Superfortresses off the production line, fitted out specially for the mission. He could pick the best pilots, navigators and bombardiers across the Army Air Force to serve under him.

Tibbets had regular meetings with scientists at Los Alamos as they discussed the bomb and how the mission could be flown. Much to the dismay and jealousy of many higher-ranking officers, Tibbets reported directly to General Groves, who in turn answered only to the country’s military and political leadership.

In late May of 1945, Tibbets’ unit was ready to move to air bases built by US naval engineers in the Marianas Island chain, 1,500 miles off the south-east coast of Japan. The 509th was based on Tinian Island, their facilities ringed by barbed wire, searchlights and armed military police. From the Marianas, hundreds of missions were being flown by squadrons of B-29s to reduce Japanese infrastructure to ashes through conventional attacks.

As they did so, the island-hoping campaign of the United States Pacific Fleet and US Army had reached its bloody climax in the fighting for Okinawa. Still, the war dragged on in the Pacific and American casualty lists grew as the Japanese put up a suicidal defence. Against this background, Tibbets was finally ordered to carry out “Special Mission No13” – the atomic attack on Hiroshima.

As he watched technicians load up the weapon, Tibbets later wrote: “Looking at the huge bomb with its blunt nose and four tail fins, I wondered why we were calling it ‘Little Boy’. It was not little by any standard. It was a monster compared with any bomb that I had ever dropped.”

B-29s fitted out as weather planes took off first, to fly ahead and report conditions over the target prior to the attack. The Enola Gay would be accompanied by three B-29s, two of which carried scientific and observational equipment to assess the bomb’s performance. All those involved – military men and scientists – still had no idea as to how Little Boy would perform and what damage it would inflict. The 10-man crew Tibbets would lead were issued with welder’s goggles fitted with Polaroid lenses to protect against the bomb blast.

In secret, he himself was provided with cyanide pills for them should the plane crash land or be shot down in Japan. If they could not drop the bomb over the target, Tibbets’ orders stated he must drop it in the ocean before returning to base. They took off at 2.45am, Tibbets scolding his co-pilot Captain Bob Lewis for attempting to handle the plane before take-off. Though Lewis had captained this particular B-29 for many weeks in training, Tibbets christened it without his co-pilot’s consent, having recently informed him he would fly the mission. Lewis had to swallow the demotion.

The mission itself would be straightforward. And it went like clockwork: six hours to the target, the actual dropping of the bomb and the six-hour return flight to Tinian. It all went to plan. At 8.15am, some 43 seconds after the Enola Gay’s released it, the weapon exploded at 1,890ft above the ground. Tibbets and his crew were by then some six miles away having rapidly turned southwards as instructed by Oppenheimer in an earlier briefing.

The blast still sent shockwaves through the plane that were strong enough for the crew to mistake for flak. As with all famous events of the Second World War, myths and legends permeate the facts. Lewis stated in his log that, watching the infamous mushroom cloud rise more than 40,000 feet into the air, he asked: “My God, what have we done?”

What he was actually witnessed to have said by Enola Gay’s navigator, Major Theodore Van Kirk, was: “Look at that son of a bitch go!” The main subject of conversation among the crew as they flew home was that the war against Japan must be over. How could they withstand such a weapon?

Tibbets himself concluded: “If Dante had been with us in the plane, he would have been terrified!”

Postwar, Tibbets would remain in the military until 1966, later working in civilian aviation. He died at home in Columbus, Ohio, on November 1, 2007, aged 92. He had been a public figure since those first newspaper reports in August 1945. To the end, he was adamant he had no regrets about Hiroshima as he told the Atomic Heritage Foundation in an interview: “Morality, there is no such thing in warfare. I don’t care whether you are dropping atom bombs, or 100lb bombs, or shooting a rifle. You have got to leave the moral issue out of it.”

With his death it was assumed he would take his rightful place as a war hero at the country’s national military cemetery in Arlington, Virginia. But he did not.

To the surprise of many of his family, close friends, fellow veterans who had served with him, and the US media, once Tibbets was cremated in a private ceremony, his ashes were transported to France and later released over the English Channel by his French-born widow, Andrea.

His grandson, Paul Tibbets IV, summarised why his grandfather had requested the nondescript ceremony over the English Channel. “The English Channel – that whole part of his life and his career – was very meaningful to him. That’s where he really proved himself, and where everything happened to him as a young officer.”

• The Hiroshima Men by Iain MacGregor(Constable, £25) is out now