The numbing afternoon when I saw a police officer die outside parliament | John Crace

The mind goes numb at times like these. A disconnect between brain and feeling. So it took me the best part of an hour to make sense of what I had seen. But the simple truth is this. Today I saw a man die. A police officer, someone I had almost certainly said “hello” to at some point over the years. Possibly even this morning. Who knows?

It was about 2.50pm when a reporter from Bloomberg came running into the Guardian office in the House of Commons to say there had been an incident outside. I ran into the offices of the Daily Telegraph that overlook New Palace Yard to see two bodies lying near the entrance to Westminster Hall, just yards from where Airey Neave had been murdered nearly 40 years previously.

I asked what had happened. “Some bloke just attacked a policeman with a knife,” I was told. “And then another policeman shot him three times in the chest.”

Armed police officers ran to the scene. Some started tending to the bodies; others stood around. Another man came running out. I didn’t recognise him. None of us did, we must have all been in shock. It later turned out he was Tobias Ellwood, a junior foreign minister whom we had all seen countless times before.

Time stretched out as people began to do CPR on both bodies. Then after what felt like an age later, but can only have been a matter of minutes, there was the noise overhead of the air ambulance preparing to land in Parliament Square.

Several armed police officers ran from New Palace Yard to talk to three paramedics dressed in yellow. They bypassed the first body – the assailant – and went straight to work on the fallen policeman. The scene became more ordered, yet more urgent. They worked for several minutes, hoping for a miracle that never came.

At some point one of the medics must have decided they had done all they could and they agreed to stop. They went to help those attending to the man who had been shot. Lines were put into him and further CPR administered. The man was taken away in an ambulance. A short while later the air ambulance took off, leaving only the dead policeman inside the parliamentary estate. His body was wrapped in a white bag on the pebbles where he had fallen.

I went back to my desk, unsure of what to do. I had come to work that day expecting to sketch prime minister’s questions and had ended up as one of many witnesses to a terrorist attack. At various points in the afternoon, with the whole of the Houses of Parliament locked down, I returned to the window to see what was going on. It was as if I was somehow hoping that I could rewind time, that I could make what had happened unhappen.