MP Tobias Ellwood was "ordered to stop" CPR on police officer Keith Palmer, who was murdered in the Westminster terror attack.

The former soldier told an inquest today that despite the risk that attacker Khalid Masood may have had a bomb in his abandoned car, his main concern was giving help to stricken PC Palmer, a former Bromley officer, who had been stabbed.

Mr Ellwood told the Old Bailey: "My brother was killed in a secondary attack in Bali (a 2002 terrorist bombing in Indonesia) ... so I was very aware of that.

"I was concerned about what would happen if things were to ratchet up, but my immediate concern was that we had somebody who was clearly badly bleeding and needed assistance."

During his rampage, Masood, 52, ploughed an SUV into pedestrians on Westminster Bridge before stabbing PC Palmer to death at the gates to the Palace of Westminster.

Mr Ellwood said he first became aware that something was wrong when he heard a "significant crash" followed by "screams".

The Tory MP for Bournemouth East then saw two waves of people with "panic in their eyes" as he made his way to Parliament through the underground passageway.

"They were shouting, 'go, go, go, go' and, 'go back, go back'," he said, before his attention was drawn to the area where PC Palmer was attacked.

"I have never seen so many armed officers with their weapons out in the Houses of Parliament," he said.

"I could see there were two bodies lying in the ground and activity around both of them.

"The nearest one was clearly a police officer with other officers attempting to give him support."

Mr Ellwood said he stepped forward, making clear who he was to the armed officers, ignoring the risk to his own safety to help administer first aid.

He told how he assessed the officer's wounds before commencing CPR, which he continued after paramedics and doctors from the helicopter ambulance team arrived.

Becoming emotional as he recalled the dramatic events when doctors opened PC Palmer's chest, he said: "Forgive me, it's sometimes easier to do the helping rather than to talk about it afterwards."

When it became clear that PC Palmer would not survive, Mr Ellwood told a doctor present: "You're going to have to order me to stop."

The medic said: "Sir, you've done your best but you do need to stop."

He described the "eerie silence" at the Palace of Westminster as it stayed in lockdown in the aftermath of the carnage.

Mr Ellwood and one other person were left with the officer's body.

He said: "We both covered the body as best we could, closed the eyes and I said: 'I'm sorry.'

"It was very, very silent, it was a very strange end to a very traumatic four or five minutes, to suddenly be left completely alone with just one other person."

The inquests into the victims' deaths continues.