Video report by ITV News Correspondent Paul Davies
Scotland Yard has slammed criticism of deputy commissioner Sir Craig Mackey's actions during the Westminster attack as "abhorrent".
The senior officer came under fire when he testified that, despite being nearby, he remained in his vehicle during the rampage.
It comes after an inquest into the attack finished and found that attacker Khalid Masood, 52, was lawfully killed when he was shot by a politician's bodyguard.
Masood killed five people, including PC Keith Palmer, when he carried out the attack on Westminster Bridge and outside Parliament on March 22 last year.
Sir Craig was accused of cowardice by staying in the car, but the chief coroner insisted that nothing he could have done would have stopped the rampage.
Counter-terror chief Neil Basu reiterated this viewpoint, saying that what Sir Craig had done was "sensible and proper".
Commander Basu said: "Craig was in a car, accompanied by two civilian staff members.
"Neither he, nor the two civilian staff, had any protective equipment with them.
"The inquest heard that his initial reaction as a police officer was to get out of the vehicle, but he was told not to do so by a uniformed officer at the scene.
"Had he done so, it would have put Craig directly in the line of fire, and prevented the protection officer from taking the shot which stopped the terrorist once and for all."
Commander Basu added: "What Sir Craig did was sensible and proper, and was intended to protect others in the car with him."
The inquest jury came to its conclusion on Friday after two hours and 22 minutes of deliberation, bringing to a finish an inquest that lasted two weeks.
Masood was shot three times by a politician's bodyguard after he killed four people and stabbed to death PC Keith Palmer.
The Muslim convert had hired an SUV to mow into pedestrians, leaving 29 people injured around the Westminster Bridge area.
He then crashed into railings at the Houses of Parliament where he used knives to continue the attack, fatally injuring PC Palmer.
The attack was only stopped when the bodyguard rushed to the scene and shot Masood.
The jury, consisting of seven men and four women, added a short narrative of the events when delivering their finding.
They found that Masood was intent on inflicting "serious harm" when he stormed through the gates to the Palace of Westminster.
He had been issued with verbal warnings but "continued to move toward the close protection officers at speed" before he was shot, the jury said.
Earlier, Coroner Mark Lucraft QC had directed the jury to return a lawful killing verdict as the bodyguard believed it was necessary to open fire in defence of himself and others.
Along with PC Palmer, Andreea Cristea, Kurt Cochran, Aysha Frade and Leslie Rhodes were all killed in the attack
They were found to have been unlawfully killed.
The inquest heard dramatic accounts of how unarmed police officers and members of the public fled after Masood killed Pc Palmer and continued to advance, clutching bloodied foot-long knives, intent on targeting more officers.
His rampage was stopped by a close protection officer identified only as SA74, on site to act as bodyguard to a government minister.
The officer shot him three times with a Glock pistol after Masood continued to run forward at him, despite shouted warnings to "get back".
SA74 gave an emotional account of how the drama unfolded, pausing during his evidence and his voice wavering as he recalled: "I was certain that something terrible was happening."
"I saw a large black male running purposefully towards me. He was carrying two large knives and I could clearly see that they were covered in blood," he told the Old Bailey.
"He was going to kill me."
After the inquest, Commander Basu said he "welcomed" the findings that Masood had been killed by security officers.
He described the officers who approached Masood as showing "great courage", and praised PC Nick Carlisle, who handcuffed the attacker while he lay prone, fearing he may be wearing a suicide vest.
PC Carlisle described how he attempted to distract Masood as he attacked his colleague PC Palmer.
"I had lined him up. I was going to strike him with a shoulder barge, rugby tackle to his right side and put him to the floor," he said.
"But when I was almost upon him he saw me coming and he turned to face me, knives up, and I had to veer away to the side."
PC Carlisle added: "I expected him to be wearing at least ballistic body armour and more likely a suicide vest.
"I went forward covered by the firearms officers and handcuffed him to prevent any sort of explosion."
Commander Basu said: "My thoughts and deepest sympathies are with the victims, their families and loved ones who have been left devastated by their loss.
"They have all endured terrible suffering as a result of one individual's barbaric actions."