Police have released CCTV stills of 17 suspects after violence erupted at a Free Tommy Robinson protest four months ago.
Hundreds of supporters of the former leader of the English Defence League descended on central London on June 9.
Scotland Yard appealed for information on Sunday and released images of 17 men they want to speak to.
Nine men were arrested during the protest, which blocked the road around Trafalgar Square.
Bottles, metal barriers and other objects were hurled at officers, five of whom suffered minor injuries, police said.
The demonstration was one of a number held in support of Robinson, who was jailed for contempt of court for using social media to broadcast details of a trial which is subject to blanket reporting restrictions.
Leeds Crown Court heard how he filmed himself and people involved in the case, in footage that was watched around 250,000 times within hours of being posted on Facebook.
Robinson, who was listed by his real name Stephen Christopher Yaxley-Lennon on court documents, was sentenced to 13 months in jail on the same day as his arrest.
He was given 10 months in jail for contempt of court, and an additional three months for beaching a previous suspended sentence.
Robinson was later freed from prison after three leading judges quashed the contempt of court finding made at Leeds Crown Court.