GETTY FILE PICTURE
Mr Palmer, who was 48, was a member of the Met's Parliamentary & Diplomatic Protection Command and had 15 years' service.
The news of his death was confirmed by Scotland Yard's top anti-terror officer Mark Rowley.
Mr Rowley said: "One of those who died today was a police officer, PC Keith Palmer, a member of our Parliamentary & Diplomatic Protection Command.
"He was someone who left for work today and expected to return home at the end of his shift, and he had every right to expect that would happen."
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