LONDON, June 29 (Reuters) - British Prime Minister Boris Johnson on Tuesday condemned the "despicable" harassment of the government"s top medical adviser, Chris Whitty, after footage emerged on social media of two men grabbing him around the head as he walked down the street. Jeering loudly and grinning at the camera, the men are seen in the film, published on Twitter, manhandling Whitty, 55, who has become one of the nation"s most prominent officials because of his regular appearances at coronavirus pandemic briefings. They hold onto him before he manages to break free, and walk away across the road looking shaken. Prime Minister Boris Johnson said the incident was "despicable". "I condemn the behaviour of these thugs," he said on Twitter. "Our hard-working public servants should not have to face this kind of intimidation on our streets and we will not tolerate it." Other ministers also echoed their revulsion, with Health Secretary Sajid Javid calling it "appalling and totally unacceptable". "This is disgusting and these thugs must be found and charged. Zero tolerance for harassing a public servant," Nadhim Zahawi, the vaccines minister, said. Police said the matter was being investigated. It was not clear from the footage when the incident took place. "We are aware of a video being shared online showing an incident in St James’s Park," police said on Twitter. "Officers spoke to all those involved at the time and their details were taken." It is not the first time that Whitty or other senior officials have faced harassment, having previously been targeted by those who are opposed to the COVID-19 vaccine rollout or lockdown restrictions. Last week, England’s deputy chief medical officer Jonathan Van-Tam was verbally abused as he walked into a government building by a protester.