- 7 updates
Detectives are questioning a group of suspected Islamist terrorists amid fears the men were plotting to launch an attack in Britain.
ITV News has obtained dramatic CCTV footage of one of a series of arrests across London, in which counter-terror police are seen tackling a 28-year-old suspect on the upmarket Westbourne Grove in west London.
This report is by ITV News UK Editor Lucy Manning:
ITV News has obtained CCTV footage of one of the four anti-terror arrests in London last night.
The video shows the 28-year-old suspect leaving a Persian restaurant in Westbourne Grove before he and another man are wrestled to the ground by a group of officers.
It is not clear whether the minibus which pulls up to the suspect is a police vehicle. Unmarked police cars attend the scene once the men are apprehended.
The British national, believed to be of Azerbaijani origin, was arrested on suspicion of the commission, preparation or instigation of acts of terrorism.
George Paul witnessed the arrest of one of the suspects in Westborne Grove and told ITV News he saw "three policemen holding down one individual - I don't know what ethnic origin he was but he was shouting.
"It was all over in ten minutes."
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.
Police are still searching six addresses and two vehicles in London following the arrest of four men in a pre-planned terrorism operation.
Two men aged 25, one man aged 28 and a 29-year-old man all remain in custody.
The Metropolitan Police said searches are being carried out at six addresses after four people were arrested on suspicion of terror offences.
In a statement, Scotland Yard said: "At approximately 19.10 today (Sunday, 13 October) four men were arrested on suspicion of the commission, preparation or instigation of acts of terrorism under the Terrorism Act 2000.
"They have all been taken to a south London police station. Two men were arrested in Mansell Street, E1. One man was arrested at a premises in Westbourne Grove W2. The fourth man was arrested in Peckham Street, SE15.
"Searches under the Terrorism Act 2000 are being carried out at six addresses in London. Officers from the MPS Firearms Unit were involved in these arrests. Public safety remains our overriding concern."
Four people have been arrested across London in a pre-planned terrorism operation, Scotland Yard said.
A man who witnessed one of the arrests on Westbourne Grove - a street lined with restaurants and boutiques in Notting Hill - said what unfolded was "quite a scene".
The man, who did not want to give his name, said: "Well, I walked by and it seemed to be a couple of guys being arrested.
"There were three."
The man said the men "looked white" and were "up against the wall".