6 August 1945: a day like today ... but no day would ever be the same again

IT WAS a heatwave morning, hot and humid, and the people of Hiroshima were up and about early, getting things done before the sun rose too high. Just after 7am an air raid alert interrupted them, but there were no bombs, so when the Enola Gay flew over an hour later it excited little more than curiosity.

The atomic bomb, aimed at a bridge in the city centre, was released at 31,000ft and was still 1,900ft above the ground when it exploded.

The light came first, a whiteness that bleached the colour from everything. Then the heat, sufficient to roast a human being half a mile away in an instant. And then the shock wave, pushing before it a black wall of dust and crunching buildings like balsa models.

After that came silence, a silence that smothered the city all day. The dead could not talk and the living would not.

The city centre was reduced to dust. Beyond it, where there was still something to burn, fire quickly took hold.

Disorientation and incomprehension afflicted all. Many thought it was just their home or their street that had suffered a direct hit, and that elsewhere all would be well.

In their tens of thousands they began moving, fleeing to the rivers or parks to escape the flames, looking for hospitals or loved ones, for help in extracting a relative from the rubble, or simply looking for a way out. Slowly they became aware of the scale of the calamity, but still without understanding.

Many in the shuffling horde were naked, the clothes scorched from their backs. Many were horribly maimed - a woman with no jaw, children without hands, people whose arms or faces had melted or carbonised, people whose stomachs had been sliced open by flying glass, people blinded and deafened. Often they sank to the ground and died without a murmur.

The fires raged all day and the sky was like twilight, occasionally releasing a shower of heavy, grimy radioactive raindrops. Violent windstorms blew up and quickly subsided.

The rivers filled with the living, who were taking refuge from the fire, and the dead, who were floating towards the sea. Most hospitals were destroyed; most of the doctors and nurses were dead or wounded . Such medical services as survived were overwhelmed. For tens of thousands there was no treatment, no food and no way out.

Overhead, American aircraft repeatedly returned to assess the damage. Of 76,000 buildings in the city, 48,000 were destroyed that first day, and 100,000 people died. The signs of radiation sickness did not appear until day two. By the end of the year 145,000, half the city's population, were dead.