Thousands of demonstrators marched from Hyde Park to the Israeli embassy in Kensington, after a week in which at least 126 people have been killed in Gaza and seven people have been killed in Israel.
The demonstration in London was organised by Palestine Solidarity Campaign, Friends of Al-Aqsa, Palestinian Forum in Britain, Stop the War Coalition, Campaign for Nuclear Disarmament and the Muslim Association of Britain.
Organisers of the march said they were protesting against evictions of Palestinians from Sheikh Jarrah (a predominantly Palestinian area of East Jerusalem), the bombing of Gaza and the deaths of Palestinian civilians.
They called for the UK government to take “immediate action”, saying: “It must stop allowing Israel’s brutal violence against and oppression of the Palestinian people to go unpunished.”
In London, videos showed protesters waved Palestinian flags and shouted “Free Palestine”, with others chanting “Israel is a terror state”.
Later, nine police officers were injured and missiles were thrown amid efforts to disperse crowds outside the Israeli Embassy. Nine people were arrested on suspicion of violent disorder, the Metropolitan Police said.
The former shadow home secretary, Diane Abbott, addressed the crowds, describing protesters as part of a “worldwide movement for justice”.
She said: “Palestinian people are having their land seized ... and they are now being killed in their homes.
“All of this is illegal.”
Former Labour leader Jeremy Corbyn told the crowds that international action provides “comfort and support” to those suffering in the conflict.
Crowds chanted “oh, Jeremy Corbyn” and threw roses as he took to the stage.
“Think what it's like being a mother or father and seeing a building bombed in front of you, knowing your family is in there, and you can do nothing,” Mr Corbyn said.
“It's our global voices that will give succour, comfort and support in those settlements alongside Gaza and all over the West Bank, East Jerusalem who are suffering at this time.
“End the occupation now. End all the settlements now and withdraw then. End the siege of Gaza now.”
Organisers of the London march said: “The bombardment of Gaza which is killing civilians including children is a war crime.
“The UK government is complicit in these acts as long as it continues to offer Israel military, diplomatic and financial support.”
Husam Zumlot, Palestinian ambassador to the UK, said: “This time is different. This time we will not be denied any more. We are united. We have had enough of oppression.
“Today, we are saying enough; enough with the complicity. Thank you for standing with us.”
Organisers said crowds totalled 100,000 and stretched back to Bayswater Road from Kensington High Street.
Protests also took place in Bristol, Manchester and elsewhere in the UK, with a demonstration planned in Glasgow’s George Square tomorrow.
Metropolitan Police said on Twitter: “A large group has gathered outside the Israeli Embassy in South Kensington. Officers are on site and continue to engage with those taking part in the demonstration. Drivers are warned to expect traffic disruption in the area.”