He's been hailed as the man who prevented the terrorist doing further damage to Britain's capital.
PC Keith Palmer, 48, was sadly stabbed to death by the attacker outside the Houses of Parliament, after confronting him for attempting to get into the Palace of Westminster.
Advert
But this wasn't the first time he'd made a heroic move.
Palmer served in the Metropolitan Police's parliamentary and diplomatic protection command and had 15 years of service under his belt.
But 10 years ago, he was part of another life-saving moment.
Advert
Credit: Metropolitan Police
He'd saved the life of one of his colleagues who was part of an on-duty road collision.
Nina, from Orpington, called radio station LBC to explain the story of Keith's bravery.
"He did save my life," she said. "So I just wanted to ring up to let everybody know what a wonderful man he was."
Nina was the passenger inside the police car that had the crash.
She said: "He was one of the police officers who saved my life.
"I owe him everything. He was a wonderful dad, and wonderful husband to his wife and everything.
"He was just fun, he was a laugh, and he cared."
Keith seemingly paid the ultimate price for the care that he showed in his job, and for his country.
"He cared about what he was doing, his job. He didn't just do his job to go and get paid," she continued.
"He actually cared about the people. He really did. He was a lovely man and everyone's going to really miss him.
Nina was medically retired after the crash and says the phrase 'oh he was a lovely person' - commonly assigned to someone after they die - is understated when it comes to Keith.
Yesterday, thousands of tributes from senior figures, to friends, and strangers, paid tribute to the police officer killed in the line of duty.
Steve White, chairman of police federation of England and Wales, said the police service is "in mourning" today but praised the service's "can do attitude".
Advert
He said that annual leave had been cancelled and police officers recalled to duty.
An online fundraising page has been set up for PC Keith Palmer's family.
Palmer was one of four confirmed victims of the London terror attacks yesterday, after two died on Westminster Bridge and the attacker was later shot dead outside the Palace of Westminster.
Mum-of-two Aysha Frade has also been confirmed as one of the victims, after she was hit by the car on the bridge near to the Houses of Parliament.
This morning, the capital attempts to continue with day-to-day life as millions of people, including MPs return to work. If anything, continuing the trending hashtag #WeAreNotAfraid.
Featured Image Credit: Metropolitan Police