Five people - including one police officer and the perpetrator - died in today's "sick and depraved" attack in Westminster.
Speaking outside 10 Downing Street after chairing a meeting of the Government's Cobra emergencies committee, British Prime Minister Theresa May paid tribute to the "exceptional men and women" of the police force who responded to the attack.
She confirmed that a single attacker drove a car into pedestrians walking on Westminster Bridge before running with a knife through the front gates of the Palace of Westminster, where he killed a police officer before being shot dead.
She vowed that "the forces of evil" would never be allowed "to drive us apart".
Mrs May said that any attempt to defeat the values that Parliament stands for was "doomed to failure".
And she vowed: "We will all move forward together, never giving in to terror and never allowing the voices of hate and evil to drive us apart."
The UK's terror threat level would remain at "severe", Mrs May said.
She praised the bravery of the police officers "who keep us and our democratic institutions safe".
"Our thoughts and prayers go out to all who have been affected, to the victims themselves and to their families and friends, who waved their loved ones off but will not now be welcoming them home.
"For those of us who were in Parliament at the time of this attack, these events provide a particular reminder of the exceptional bravery of our police and security services who risk their lives to keep us safe.
"Once again today, these exceptional men and women ran towards the danger, even as they encouraged others to move the other way."
