More than 150,000 people marched from the BBC studios in Portland Place, past the US embassy in Grosvenor Square to Hyde Park, in a protest called by Palestine Solidarity Campaign and other organisations. It was the third mass march through London in support of Gaza in three weeks. It was also the biggest, and formed part of a global Day of Rage, with people marching in cities across the globe to show solidarity with Gaza under attack:
http://www.palestinecampaign.org/biggest-london-rally-yet-gaza/