The man was allegedly surrounded by a group of protesters, who had attended an earlier demonstration, and verbally abused outside St James's Park tube station, on Wednesday (May 27) at around 6pm.
Officers wish to speak to the individuals involved in the incident - in which the man had left the station and was making his way to a nearby bus stop when he became victim to threatening and intimidating behaviour - police said.
He was prevented from returning to the tube station or getting to the bus stop until police arrived at the scene and escorted him to their vehicle.
A number of people attempted to prevent them from leaving. The man was driven away from the group to safety.
Police want to hear from anyone who may recognise the male trio pictured.
Any information provided will be treated in confidence.
If you recognise any of the three men or have any information contact the Public Order Investigation Team on 0208 246 0076 or Crimestoppers anonymously on 0800 555 111.
On Sunday (May 31), a 20-year-old man was arrested and charged with a Section 4 Public Order Act 1986, using threatening words or behaviour.