Organisers said the vigil sought to show that “we will not be divided”.
Thousands of people – from police officers to faith leaders and members of the public – linked hands on Westminster Bridge in a show of defiance a week after the terror attack in the capital.
The Hands Across Westminster Bridge organisers said the vigil sought to show that “we will not be divided”, linking “all nations, faiths, orientations and sexes”.
A statement on the Metropolitan Police Federation website said officers who attended the scene of the attack were urged to “come to pay their respects, as well as victims, witnesses and anyone else”.
The bridge, still adorned with floral tributes to the victims, was closed to traffic.
Nurses and doctors from St Thomas’ hospital, where many of the injured were treated, joined those on the bridge.
Children aged nine and 10 from Al-Sadiq and Al-Zahra Schools held yellow roses and held signs which read “Islam says no to terror” and “please don’t kill innocent people” as they walked across the river.
Hundreds of members of the Ahmadiyya Muslim Youth Association were on the bridge, wearing T-shirts with the message “I am a Muslim, ask me anything���.
Zafir Malik, an imam from the association, said they were asked by the police to come along to show solidarity, and that they wanted to “show that what happened here last week had nothing to do with the so-called religious aspect that this has been given.
“(It has) nothing to do with Islam, nothing to do with what we believe in and preach on a daily basis.
“We’re here to show that we are united with our fellow countrymen and remembering those who have fallen, especially Pc Keith Palmer. We are here and showing our solidarity for the country.”
Vigils were also held across the country to coincide with the Westminster event.
Those gathered on the bridge fell silent at 2.40pm – the time the first call was made to police exactly seven days ago.
Rain began to fall as the vigil paused for a minute’s silence for the victims on the bridge, in the shadow of the Palace of Westminster, where the deadly attack took place.
Police officers also held a minute’s silence outside New Scotland Yard.
Acting commissioner of the Metropolitan Police Craig Mackey said: “This afternoon is about remembering the victims of last week’s events. Our thoughts, our prayers, go out to everyone who was affected by the events last week.
“I would urge you, if you get time, to go on to the bridge, talk to Londoners, talk and get a feel for this great city and how it’s come together in responding to these events.”