A speech at a protest rally that likened NHS nurses and doctors to Nazis executed after World War Two has been condemned by nursing leaders.
The Metropolitan Police said officers were assessing a video of the speech by former nurse Kate Shemirani during Saturday's protest in central London.
The Royal College of Nursing said it was "reprehensible and could put nursing staff at risk".
London mayor Sadiq Khan said Ms Shemirani's comments were "appalling".
Thousands attended Saturday's event at Trafalgar Square, billed as a "live debate" on Covid-19 and linked to several similar demonstrations across the world.
Some attendees expressed anti-vaccination views, while others questioned remaining restrictions and the use of vaccine passports.
Ms Shemirani, who has been criticised, including by her own family, for promoting virus conspiracy theories, made a speech comparing NHS workers to Nazis convicted at the Nuremberg trials.
Speaking about the vaccine, she encouraged the crowd to challenge vaccinators about its safety.
She added: "At the Nuremberg trials, the doctors and nurses stood trial and they hung."
Ms Shemirani went on to appeal to doctors and nurses to "stand with us, the people".