London terrorist 'British-born' who was previously investigated by MI5
LATEST: British Prime Minister Theresa May has confirmed the terrorist who killed four people and injured 29 others is British-born and was investigated previously over his "violent extremism".
A mother-of-two has been named as one of three people killed in London on Thursday.
Aysha Frade was walking across the Westminster Bridge on Wednesday to pick up her two daughters, aged eight and 11, when she was struck by a four-wheel-drive.
The 43-year-old mother was hit by the terrorist’s Hyundai and then thrown under a bus.
Speaking to a shell-shocked parliament, attended by some of the politicians who tried desperately to save the life of stabbed police officer Keith Palmer, Prime Minister Theresa May conceded the attacker was known to MI5 intelligence.
"Some years ago, he was once investigated by MI5 in relation to concerns about violent extremism," she said.
"The case is historic, he was not part of the current intelligence picture.
"There was no prior intelligence of his intent or the plot."
The man, who was shot dead after he fatally stabled constable Palmer, remains unnamed.
Seven people have reportedly been arrested after British police conducted raids following the Westminster Bridge terror attack.
Police now say four people, including the attacker, were killed and 29 others were injured in the horrific attack that has shocked London and the world.
Armed police stormed an apartment in Birmingham just hours after the terror attack, and reportedly arrested three men.
A further four people have been arrested after raids at five addresses in London, Birmingham and elsewhere in the UK in connection with the London terror attack, the Met's senior anti-terror officer says.
It's believed the vehicle used in the horror attack was rented from a Birmingham agency, but that has yet to be confirmed.
The attacker used an SUV to run down pedestrians along the Westminster strip, before crashing into the parliament fence opposite Westminster Tube Station, near Big Ben.
Armed with a knife, the terrorist jumped out and ran around the corner to the entrance gates where he fatally stabbed Police Constable Keith Palmer.
The guard's colleagues then shot the man dead.
PC Palmer was a 48-year-old father-of-two, while a woman aged in her 40s and a man aged in his 50s were also killed in the attack, London police confirmed.
Panicked tourists were forced to run for their lives, including a South Australian mother who has undergone surgery on her injured foot.
"We heard gunshots, we thought they were gunshots," one witness said.
"I hear bang, bang, twice.
"People were running like mad... and I was like 'why are they running?'."
A number of politicians, including Foreign Office Minister Tobais Elwood, came rushing out to help the wounded, with Elwood performing CPR on the officer.
"Our thoughts and prayers go out to all who have been affected," PM Theresa May said.
"To the victims themselves, and to their families and friends, who waved their loved ones off, but will not now be welcoming them home."
The Department of Foreign Affairs has warned Australians to exercise caution and remain vigilant travelling to London.
