The director of the Independent Office for Police Conduct, Amanda Rowe, said: “Police officers must treat members of the public with respect and courtesy during the course of their duties.
“This was a distressing incident for the woman, who was handcuffed in public in front of her child, and the language used by PC Lathwood was disrespectful and unprofessional.”
Ms Rowe said the incident had become “high profile” after a video of the arrest shared on social media went viral.
She explained that it caused “significant public concern at the time”, particularly in the Croydon community.
The director said the interaction “continues to have a lasting impact on the woman involved”.
Paula Dodds, chair of the Metropolitan Police Federation, said: “Short video clips of incidents viewed from the comfort of sterile and calm environments rarely take into account what police officers in London encounter on a daily basis – or provide a genuine understanding of the true nature of our difficult and dangerous job.
“Police officers have no issue with scrutiny and accounting for their actions and use of force – but this has to take into account the dynamic and split-second challenges and the reality of our challenging role.
“PC Lathwood can finally put this incident behind him and carry on his career. We ask that he and his family are now left alone to get on with their lives.”