An inquest into the death of St Neots man Richard Davies has heard the police firearms officer who fired the fatal shot had only been at the scene for between 30 and 40 seconds.

The officer, who is being referred to as I7, to protect his identity, told the hearing at Peterborough Town Hall on Monday that he believed the three Davies children were still in the house when he arrived at Duck Lane on the night of October 21, 2015.

He said he was aware that three children had been tied up and threatened with a knife by their father ,but did not remember hearing updates via the police radio to say they had escaped and said his tactical briefing was “shouted across the car park” by the officer known as N6 just before he and officer C1 made their way to the scene.

He did, however, remember hearing a message to “consider a critical shot to protect the public” and it was put to him by Heather Williams, representing the Davies family, that he had “selective hearing”.

“So C1 didn't tell you the children had escaped and you didn't think to ask?” said Miss Williams.

“That's correct, I was concentrating on driving,” I7 said.

As I7 pulled up outside the house, Mr Davies fired another shot and he and C1 were told to go round to the back of the house, but I7 said he took cover behind a vehicle and denied hearing the instruction.

He told the jury he looked up and could see Mr Davies at an upstairs window.

“I could see he had something in his hand, it looked like a handgun with a slim barrel, but it was slightly longer. He was side-on and leaning forward and his hands were pushed out.”

When asked by assistant coroner Nicholas Moss to describe the direction of fire, he replied: “It looked to me as if it was being pointed towards the two parked police cars.”

I7 then saw what he described as a puff of smoke and a flash of light and heard another shot.

“I brought my weapon up to the window but Mr Davies ducked,” he said.

“I believed that he had already shot at police three times and was about to do it again. It was my belief that there was an immediate threat so I aimed at the centre of his chest and fired a shot to stop him firing again. I was worried he was about to kill one of my colleagues or a member of the public.”

“As I fired, Mr Davies fired, it was almost simultaneously. I heard two bangs and there was a flash of light and a puff of smoke.”

Asked by Mr Moss what happened next, he replied: “I saw Mr Davies jerk backwards.”

Miss Williams then asked: “Is it possible that you were under pressure and you lost your composure and discharged your weapon when you shouldn't have done,” to which I7 replied: “No”.

Miss Williams continued: “You had only been at the scene for a very short time when you fired your weapon?”

“Yes that's correct,” said I7.

Miss Williams then added: “You were under pressure, you panicked, lost your head a bit,”

“No” he replied.

“You say you had not been told the children were out of the house, so you fired believing they were still there. You fired at the window and they could have been standing by the window just behind the curtains,” Miss Williams said.

“I fired to stop Mr Davies firing,” said I7.

The inquest heard that I7 joined the police force in 2003 and had been a police firearms officer for eight years. During that time he had signed out a firearm on 2,880 occasions, been given full authority to fire on 880 occasions, but had never fired his G36 Carbine until the incident in Duck Lane in 2015.

The hearing continues.