A man hurled anti-Semitic abuse through a megaphone from a convoy of cars draped in Palestine flags.
The group of protesters have been roundly condemned after the racist and foul-mouthed rant shocked passers-by in North London.
Footage on social media showed a convoy of cars covered with Palestinian flags passing down Finchley Road, with passengers heard to shout offensive language and threats against Jews.
One man shouted "f*** their mothers, f*** their daughters.... rape their daughters, we have to send a message to them".
The convoy was passing through a part of London where there is a large orthodox Jewish population at the end of a week in which lives have been lost in Israel and Palestine.
Boris Johnson has condemned what he called “shameful racism” while the Metropolitan Police have said they are aware of the incident in the St John’s Wood area and are carrying out urgent enquiries to identify those responsible.
“This sort of behaviour will not be tolerated,” the force said.
The footage, along with other incidents that have emerged following large pro-Palestine rallies over the weekend, has received cross-party criticism.
Mr Johnson said: “There is no place for anti-Semitism in our society.
“Ahead of Shavuot, I stand with Britain’s Jews who should not have to endure the type of shameful racism we have seen today.”
Labour leader Sir Keir Starmer described the incident as “utterly disgusting.”
“Anti-Semitism, misogyny and hate have no place on our streets or in our society,” he said.
“There must be consequences.”
Referring to the video of the convoy, Housing and Communities Secretary Robert Jenrick said: “This, on the streets of London, is deeply disturbing.
“Vile, criminal hatred like this must not be tolerated.”
In a statement Mr Jenrick continued: “Whatever your view of the conflict in Israel and Gaza, there is no justification for inciting anti-Jewish or anti-Muslim hatred.
“The incidents of anti-Semitism we have seen in recent days have been shameful.
“Some of the language used on marches this weekend and in posts on social media is intimidating, criminal and racist.
“We must not tolerate this vile, shameful hate in our country. These actions must stop.”
Cabinet minister Michael Gove described another video appearing to show protesters shouting anti-Semitic abuse as “deeply concerning”.
Thousands of Palestinians have been forced to flee their homes after a week of sustained conflict.
Since last Monday night, Palestinian militant group Hamas has fired hundreds of rockets into Israel, whose military responded by barraging the Gaza Strip with tank fire and air strikes.
At least 145 people in Gaza and eight in Israel have been killed since the fighting erupted.
