This is the Guardian.

Today, the secret victims of the UK's war on Islamic State.

In 2016, the UK was fighting a battle to retake the Iraqi city of Mosul from Islamic State.

There were a few British troops on the ground, but mostly for the UK, it was an air war

fought with jets and drones.

And something about that war has always nagged at me.

Emma Graham Harrison is a foreign correspondent with the Guardian and Observer.

Britain dropped thousands of bombs and missiles on Mosul, and it claims not a single one killed any civilians.

Not a single one.

The Ministry of Defence still claims that today that its campaign against Islamic State in Iraq was a perfect war.

The thing is, we don't believe this is true, and now we have evidence.

A few years ago, the US military declassified the transcripts of hundreds of conversations of pilots operating drones above Iraq and Syria during the war against Islamic State.

The nationalities of the pilots, whether they were British, American or from somewhere else, were all redacted.

But the transcripts paint haunting scenes.

There's one from late 2016.

Inside their control room, the pilots can see ISIS-fights inside a building.

They're ordered to fire. They launch a hellfire missile.

And the screen fills with smoke and debris.

Only then do the pilots realize their mistake.

They can see it on the screen.

Two children, someone says.

A new Guardian investigation has revealed those pilots were almost certainly British.

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