The estate agent, of Romford, east London, has since claimed he just wanted a selfie and has apologised for making Prof Whitty feel uncomfortable.
But Met Police have now charged Hughes with common assault after “reviewing video footage”.
Hughes will appear at Westminster Magistrates’ Court later this month.
In the short clip, a police van could be seen parked in the background before officers spoke to Hughes and his friend Jonathan Chew, 24, Kent Live reports.
Police initially said that, when officers spoke to Prof Whitty, he had not suffered any injuries and, at the time, did not wish to press charges.
But in a statement today, the force said: “Detectives investigating an incident that took place in St James’s Park on Sunday, June 27, have charged a man.
“Lewis Hughes, 23, of Wigton Way, Romford, was charged with common assault on the evening of Thursday, July 1. He was charged by postal requisition and will appear at Westminster Magistrates’ Court on Friday, July 30.
“At approximately 7.20pm on Sunday, June 27, officers in St James’s Park became aware of a man being accosted by a group of men. They spoke to the victim and checked his welfare. He had not suffered any injuries.
“Officers subsequently reviewed video footage which emerged after the incident and the matter was referred to the Public Order Crime Team. Enquiries continue.”