London Calling.
London Walks connecting.
This is London. This is London Walks. Streets Ahead. Story time. History time.
Red light.
A man waits at the kerb.
Traffic goes past.
Green light.
The man steps into the road.
And the world changes.
I mean that almost literally.
We’re in Bloomsbury.
Southampton Row. Where it meets Russell Square.
And the date is September 12th, 1933.
Ninety-three years ago today.
It’s not much of a morning.
Grey. Cool. Damp.
London doing grey, cool and damp. Something London has had quite a lot of practice at.
And standing there waiting for the lights to change is a 35-year-old Hungarian physicist.
His name is Leó Szilárd.
And there’s a lot going on inside Leó Szilárd’s head.
There usually was.
He was one of those people whose brain seems to have been permanently set a couple of gears higher than everybody else’s.
Born in Budapest in 1898. Jewish family. Brilliant at mathematics and physics. Studied in Berlin. Knew Einstein.
And then came 1933.
Hitler.
Szilárd saw what was coming.
He got out of Germany and came to Britain.
So here he is.
A refugee in London.
Walking through Bloomsbury.
On his way to the British Library.
Thinking.
And that’s important.
Because Szilárd was a great walker.
He thought on his feet.
Which immediately makes him an honorary London Walker.
Now, something he’d read had annoyed him.
And sometimes annoyance is extremely productive.
The great physicist Ernest Rutherford had been talking about the possibility of releasing useful quantities of energy from atoms.
Rutherford was one of the giants.
The man who had helped reveal the structure of the atom.
And Rutherford wasn’t having it.
Anybody who thought atomic transformations could provide a practical source of power, he said, was talking…
moonshine.
There’s our word of the day.
Moonshine.
Lovely word.
Originally, of course, exactly what it says on the tin.
The light of the moon.
But by the nineteenth century it had acquired another meaning.
Something unreal.
Nonsense.
Humbug.
Fantasy.
And, separately, especially in America, illicitly distilled alcohol.
But Rutherford’s moonshine was nonsense.
Forget it.
Atomic power?
Pie in the sky.
Moonshine.
And Szilárd didn’t like being told that something was impossible.
So he walked.
And thought.
And walked.
And thought.
Until London stopped him.
Red light.
Southampton Row.
Russell Square.
He waits.
And then…
Green light.
Szilárd steps off the kerb.
And as he crosses the road, the idea comes to him.
Suppose you had an atomic nucleus.
And suppose you hit it with a neutron.
And suppose that process released not one neutron but two.
Those two neutrons might hit two more nuclei.
Which might release four neutrons.
Four becomes eight.
Eight becomes sixteen.
Sixteen becomes thirty-two.
And suddenly you’ve got something that feeds itself.
A reaction causing another reaction causing another reaction causing another reaction.
A chain reaction.
That’s what flashed into Leó Szilárd’s mind as he crossed a London street.
He didn’t yet know which element would do it.
He didn’t know how it could be made to work.
Indeed, nuclear fission itself hadn’t yet been discovered.
That would come five years later.
But the idea was there.
And Szilárd immediately understood something else.
Something chilling.
If such a reaction could be achieved, enormous amounts of energy might be released.
Energy for industry.
And energy for a bomb.
Think about that crossing for a moment.
Behind him, metaphorically speaking, is the old world.
In front of him is the nuclear age.
And the dividing line between them is a London kerb.
There’s another extraordinary ingredient in this story.
H. G. Wells.
London’s own great prophet of things to come.
Szilárd had read Wells’s 1914 novel The World Set Free.
And Wells had imagined weapons powered by atomic energy.
He even called them atomic bombs.
Science fiction had got there before science.
Szilárd never forgot the book.
Nor did he forget that September morning.
The following year he filed a patent covering the idea of a neutron-induced nuclear chain reaction.
And because he understood the military implications, he eventually assigned the patent to the British Admiralty so that it could be kept secret.
Fast-forward.
War is coming.
Nuclear fission has now been discovered.
And Szilárd is terrified that Nazi Germany may build an atomic bomb.
So he goes to another refugee physicist.
An old acquaintance.
Albert Einstein.
Szilárd helps persuade Einstein to put his name to a letter warning President Franklin Roosevelt about the possibilities of uranium and nuclear weapons.
That letter helps set America moving down the road that eventually leads to the Manhattan Project.
And here the story becomes almost unbearably poignant.
Because Szilárd had helped open the door.
And then he tried desperately to stop mankind charging through it.
By 1945 Germany had been defeated.
The immediate fear of a Nazi atomic bomb had gone.
Szilárd drafted a petition urging President Truman not simply to unleash this new weapon on Japanese cities.
Scientists signed it.
The bomb was dropped anyway.
Hiroshima.
Then Nagasaki.
So there’s something haunting about our man at the traffic lights.
He sees the possibility.
He sees the danger.
He helps make sure his side gets there first.
And then he tries to pull the brake.
All of that is still in the future on September 12th, 1933.
For now he’s just a Hungarian refugee in Bloomsbury.
Waiting to cross the road.
Which is why I love this story.
History usually gets monumentalised.
Palaces.
Battlefields.
Cabinet rooms.
Laboratories.
Men around enormous tables signing enormously important documents.
But sometimes history happens at pavement level.
Sometimes it happens while you’re waiting for the lights.
A thought.
A green light.
A foot comes off the kerb.
And nothing is quite the same afterwards.
And there’s a final little London irony here.
Rutherford said atomic energy was moonshine.
Szilárd walked out into the London drizzle and thought about it.
And within a few yards he had conceived the idea that would prove Rutherford spectacularly wrong.
Though perhaps Rutherford would have preferred to have been right.
So next time you’re in Bloomsbury, go to Southampton Row.
Stand by Russell Square.
Wait for the red light.
Don’t look at your phone.
Just wait.
Think.
Then the little green man appears.
Step off the kerb.
You probably won’t invent the nuclear age.
But then again…
Leó Szilárd probably wasn’t expecting to either.
You’ve been listening to the London Walks podcast.
The word of the day is moonshine.
And today’s date is September 12th.
The anniversary of the morning when a London traffic light turned green.
And the world changed with it.
See you tomorrow.