A bodyguard who shot dead Westminster attacker Khalid Masood broke down in court as he said he believed "he was going to kill me".
The close protection officer, identified only as SA74, said he told Masood, 52, to "get back" as the attacker ran towards him with two large knives covered in blood in the Palace of Westminster on 22 March 2017.
His voice broke as he told Masood's inquest at the Old Bailey: "He was going to kill me.
"As soon as I saw that threat, my pistol was drawn and I was pointing it at him.
"After shouting at him to drop the knives and perceiving no change in his demeanour, I fired the pistol."
During Masood's rampage across Westminster Bridge he killed four people and injured 29 others, before knifing unarmed PC Keith Palmer to death as he guarded the Carriage Gates into New Palace Yard.
SA74 killed Masood by shooting him three times with his Glock pistol.
The jury was shown dramatic CCTV of a blurred SA74 and his colleague, SB73, running through the yard towards Masood with guns outstretched, moments after the Masood stabbed PC Palmer.
Both officers had been waiting for the minister they were assigned to when the attack happened.
They were granted anonymity at the inquest, giving evidence beneath the public gallery as the media listened via video link from another room.
SA74 said he heard a loud "explosion" as Masood's car crashed, then heard police officers shouting as they ran towards him.
"The batons were extended and they were frantically moving towards me trying to get away from something or someone," he said.
He paused for a long time before saying: "I did not know what was happening but I was certain that something terrible was happening."
He had been a police officer since 2002 and became an authorised firearms officer in 2008 before starting as a close protection officer in 2015.
SB73 told jurors how his colleague risked his own safety to handcuff Masood then tried to save his life as he lay dying on the floor.
"At that time he was still breathing. His chest was still rising and falling. He was going grey," SB73 said.
"He basically stopped breathing so I started CPR - chest compressions."
He added that if SA74 had not shot Masood, he would have done so as he saw "no alternative".
Despite this, he said he did not want to use "deadly force" - neither did his colleague.
Jonathan Hough QC, for the coroner, asked if there was a risk because "he might have a bomb" and the officer agreed.
Hugo Keith QC, for the Metropolitan Police, suggested SA74 had no option but to shoot Masood to prevent him from killing the officer and others.
SA74 said "yes" and agreed he had "no doubt as to his plan and obvious intention" because he "never slowed down, changed direction...kept on coming at you".
Masood's inquest is due to last until the end of next week.