A woman crushed to death by a falling window pane was in “exactly the wrong place at the wrong time” eyewitnesses said.

She was pronounced dead at the scene after being struck while passing by building works at Hanover Square, near Oxford Circus.

A man who was delivering electrical cables to the area made the 999 call at around 11:30 on Thursday said the woman was “flattened” and he thought he saw her “draw her last breath”.

The man, who did not want to be named, said: “I heard this incredible loud bang. The guy next to me said: ‘What the hell is that?’, pointing. I turned round and the frame was on the ground and I was hoping it was a coat underneath, but then I saw an arm.”

He said it took five of his colleagues and around five more workers from the area to lift the concrete frame off the woman.

“I realised it was a person underneath so I phoned 999. The operator asked me to go closer to the victim so I got off the back of my wagon and went over. There was a woman who said she was a doctor who wanted to perform CPR and there was somebody giving her mouth-to-mouth. Her eyes were open and I saw her hand move and then I think I saw her last breath and then the light went out, she’d gone.

“You’d have more chance of winning the lottery than that happening to you. She was in exactly the wrong place at the wrong time.”

An air ambulance, two cycle responders, two ambulance crews and members of the hazardous area response team were sent and extensive efforts were made to resuscitate the woman, a London Ambulance Service spokeswoman said.

A Health and Safety Executive (HSE) spokeswoman said they were aware of the incident and were ‘making initial inquiries’.