Footage has emerged of the horrifying moment a woman fell into the River Thames as a terrorist ploughed into pedestrians on Westminster Bridge.

Hundreds of people fled the area as the attacker mowed down several members of the public with his car.

The video shows the speeding 4x4 driven by the suspected assailant mounting the pavement, followed by the woman plummeting into the water below.

She was later pulled alive from the river and was, last night, undergoing urgent medical treatment for “serious” injuries.

It was unclear whether the woman, who has not been identified, jumped or was knocked into the river.

A spokesman for the Port of London Authority, which looks after safety on the River Thames, said last night: “A female member of the public was recovered from the water near Westminster Bridge. She is alive but undergoing urgent medical treatment on a nearby pier. We believe she fell from the bridge.”

The black-clad perpetrator, armed with two knives, mowed his car through a crowd of people including schoolchildren on the bridge before crashing his car into railings outside parliament.

It was there he fatally stabbed PC Keith Palmer, before being shot dead by armed officers.