"Actor Eddie Marsan questioned why some people did not condemn Hamas after its attack on Israel.
Mr Marsan, who is not religious, said: 'Following the events of October 7 there were those who rushed to condemn the destruction of Gaza and the loss of innocent life, which is completely right.
But there were many who were hesitant to acknowledge or condemn the actions of Hamas against Israel and to call for the hostages to be released.
'And when I saw this I asked a Jewish friend of mine in the film business 'why can't they do both?'
'And they said 'it's because they're afraid, because they're afraid of the backlash'.'
He also called for moderate people to 'face down extremism and bigotry'.
'Fundamentalists always scream loud to drown out the voice of reasonable people, moderate people,' he said.
'Well in my experience people aren't moderate because they're turning a blind eye to injustice, people are moderate because they can see both sides of the debate, both sides of an argument, and they can sense the greater truth.
'But I think now it's time for moderate people in this country to stand up and face down extremism and bigotry and antisemitism and Islamophobia and all forms of racism.
'So I'm here today to defend my culture, my culture is diversity and I'm proud of my culture.
'And I'm also here to stand in solidarity with my Jewish friends, the people I grew up with, the people I went to school with, the people I work with, and I tell you all you are not alone.'
Former EastEnders actress Tracy-Ann Oberman told marchers: 'We're seeing a frightening and swift rise in antisemitism, Jewish attacks on our children not being able to go to school wearing their blazers with a Jewish insignia or skullcaps, our children and ourselves advised to take off any sign of being Jewish.
'I have so many friends and neighbours and people who contact me on social media saying they will take their mezuzahs off their doors, that they feel frightened, they feel isolated and alone.
'But we are not alone. We are a successful and flourishing multi-ethnic and multi-faith capital city of a multi-ethnic and multi-faith country.
'A tolerant democracy where all racism, including racism against Jews, is not tolerated.
'We have to call out antisemitism for what it is, it is an incitement to hatred, it is an incitement to divide.'"