Pc Keith Palmer's actions stopped the Westminster attacker killing others

Sadly, I don't recall how many times I walked passed Pc Keith Palmer.

A familiar face under a police officer's helmet - one of many who would let us into and out of the Palace of Westminster.

They are there every morning and evening, every weekday and weekend.

Rarely did I think how dangerous their job was.

On the front line, the very front line, should an attack ever happen.

On Wednesday it did.

And Pc Keith Palmer was on that line. Right at the front.

Unarmed. But there.

And he - along with his colleagues - stopped a killer from murdering any more.

Three people were murdered before Pc Palmer, but he was the last.

The attacker got through the gates and onto the Parliamentary estate.

But he did not get very far.

And that's because of Pc Palmer and those armed and unarmed officers with whom he served.

As the Met Police's Counter Terrorism Chief, Mark Rowley said on Wednesday night: "He was someone who left for work today expecting to return home at the end of his shift - and he had every right to expect that would happen."

Pc Keith Palmer was a husband and a father, a police officer for 15 years and a former soldier in the Royal Artillery.

He was 48.

While Chris Ship is now ITV News Royal Editor, he was previously deputy political editor.