Westminster attacker was British-born, known to intelligence services

“What I can confirm is that the man was British-born and that some years ago he was once investigated by MI5 in relation to concerns about violent extremism,” she told lawmakers, but noted he was considered a peripheral figure.

“The case is historic, he was not part of the current intelligence picture.”

May, who did not disclose the suspect’s name, said there had been no prior intelligence of his intent nor of the plot, noting also he is believed to have acted alone and that there is no reason to believe "imminent further attacks" are planned.

May said terrorism would not prevail as she rallied the country to carry on with its everyday business and stick to British values in response to the attack on parliament.

"At this time it is so important that we show that it is our values that will prevail, that the terrorists will not win, that we will go about our lives showing that unity of purpose and the values that we share as one nation going forward and ensuring that the terrorists will be defeated," she told parliament.

(FRANCE 24 with AP, REUTERS)