Supporters of pro-Palestinian demonstrators jailed for their roles in violent protests outside the Israeli Embassy say the sentences are a result of "state racism" against Muslims.
At least 22 people have so far been handed jail terms ranging from eight months to two and a half years. More are awaiting sentencing.
Thousands attended demonstrations outside the Israeli Embassy in Kensington in January last year. More than 60 were later charged, the majority with public order offences.
Police said protesters threw placards and sticks and kicked officers. One group entered a branch of Starbucks close to the embassy and threw mugs at police.
At a crowded meeting in Parliament on Tuesday, supporters called for those already jailed to be immediately released and said the sentences were a "direct attack on the Muslim community" by the government and police.
Respect MP George Galloway MP said: "It's a melancholy fact that Israel is a state, it has an embassy and the embassy must be protected. But it's one thing stopping people getting through the police lines and another pro-actively attacking protesters."
He said some offences were "trivial", such as the throwing of a plastic water bottle at the gates of the embassy.
Stop the War Coalition chairman Andrew Murray said: "This is political justice for a political purpose of the most brazen sort. These sentences are extraordinary for the crimes alleged to have been committed. Every single protest had some degree of police harassment beyond the scale we have had before."
He called for an independent inquiry into the Metropolitan Police's handling of the protests. At least 33 complaints against the police have been dismissed by the Met without referral to the Independent Police Complaints Commission.
Campaigner Joanna Gilmore said the 119 arrests after the protests were the highest for a political demonstration since the poll tax riots in 1990. A 12-year-old boy was the youngest person arrested.
"These were people previously of exemplary character. They were treated like terrorists, not ordinary criminals," she said.
Sentencing the first batch of offenders at Isleworth Crown Court a fortnight ago, Judge John Denniss said he hoped the jail terms would be a deterrent against such violent protest.
He said: "Peaceful protesting is the hallmark of a truly democratic society. They may sometimes even be boisterous. But what happened on January 10 goes way beyond this and warranted a measured response from the police."
The Metropolitan Police said it could not comment on its handling of the protests until the hearings and sentencing are completed.
Jon Benjamin, chief executive of the Board of Deputies, said: "It is entirely right that those who used the conflict in Gaza as an excuse for hostility and vandalism be harshly punished - and it is entirely wrong and very dangerous to suggest that the sentences are politically motivated."