The world has reacted in disgust to pictures of the indiscriminate slaughter of civilians in Gaza, including women and children, since Israel launched an offensive against Hamas 19 days ago.
In France, several hundred people also flouted a ban to protest after an attempt to halt yesterday's demonstration following an attack on a synagogue and Jewish-owned shops in a Paris suburb. The demonstrators ignored calls from Bernard Cazeneuve, the interior minister, for the ban to be observed, after he claimed chatter on social networks had indicated a risk it could become a "cortège of violence".
Other pro-Gaza demonstrations were also mounted in cities around the globe, including Dublin, Singapore, Washington DC, San Francisco, Auckland and Melbourne.
Israel launched its offensive almost three weeks ago in an effort to stop Hamas from firing rockets from Gaza. The Israeli army, which has sophisticated military equipment purchased from the West, is also seeking to destroy tunnels dug by militants to infiltrate Israel.
In London, the protesters caused traffic jams around Hyde Park and the West End as they marched from the Israeli embassy to Whitehall, berating David Cameron and chanting: "This is not a war. This is not a demonstration. This is a massacre."
The mood was staunchly pro-Palestinian. Placards included slogans such as "Stop the killing" and "Free Palestine", while the protesters chanted "Israel is a terror state", "Gaza don't you cry, we will never let you die", and "Allahu Akbar".
Christina Stead, 48, from Kensington, said: "Israel is trying to exterminate the people of Palestine. That makes me feel quite helpless. I think everyone should participate."
Lesley Hoskins, a historian from north London, was in the crowd with her children and grandchildren. "The situation is appalling. We are here because people need to know it's important so that the British and Israeli government can't just go on thinking this is OK," she said.
Chris Cook, 30, a construction worker from London, said: "I believe this has gone too far for too many years now. The fact that about 10 children a day die is just outrageous."
International Development Secretary Justine Greening announced that the Government is to provide an additional £2m in emergency assistance to the United Nations Relief and Works Agency's Gaza Flash Appeal. It brings the amount released this week to £7m, with the money funding basic shelter, blankets, hygiene kits, nappies and other vital supplies for the tens of thousands of people forced to flee their homes.
Greening said: "It is essential that civilians are protected and all sides must allow aid agencies access to get to those in desperate need."