A group of suspected Islamist terrorists are being quizzed by detectives amid fears the men planned to launch an attack on British soil.
Armed police fired special ammunition designed to breach doors or burst tyres at a car during one of a series of dramatic anti-terror raids across London.
Counter terrorism officers forcibly stopped the vehicle on Mansell Street, near the Tower of London, with so-called Hatton rounds and arrested two men, both aged 25.
A 28 year old man was also arrested in Westbourne Grove and a 29 year old was held in Peckham Street, south-east London, during last night's MI5-assisted operation.
All the men have been arrested on the suspicion of the commission, preparation or instigation of acts of terrorism, police say.
More top news
A joke about Southern rail has come runner up in a national competition to write the best modern Christmas cracker joke.
The victim was hit as she crossed the road at a pedestrian crossing in Tulse Hill.
The 24-year-old was unarmed and the incident is not being treated as terror-related.