A police officer who kicked and hit a mother as she sat by the hospital bed of her sick child, leaving her with more than 40 injuries, has been cleared of actual bodily harm.

Warren Luke, 38, a Metropolitan police officer, was accused of repeatedly kicking and punching the 41-year-old woman, who, hospital staff had said to him, was refusing to leave. But a jury at Wood Green crown court on Thursday cleared Luke of committing any crime.

The mother, who cannot be named for legal reasons, was caring for her seven-year-old daughter, who suffers from cerebral palsy, when the incident happened at a London hospital in December 2013.

The court heard how an argument ensued when the mother refused to leave the hospital room at the request of staff and Luke was one of four police officers called to the hospital to resolve the incident.

In a video interview played to the jury, the mother said Luke had told her: “‘You’ve got to leave, you’ve got to leave’. I kept playing with my daughter and then I saw him moving towards me. He was kicking me and kicking me. He had one hand on my head. When I fell on the bed he grabbed my hair and banged my head. I was screaming. I couldn’t defend myself. My ex-husband ran in and shouted, ‘why are you kicking my wife?’”

Luke, who has been a police officer for six years, told the court that the mother’s behaviour had been “escalating” and he felt the child was at risk of injury. He said he had contemplated using a baton or CS gas but decided that that was not an option.

Instead, he told the court, he struck the mother repeatedly on her left bicep and then decided to try a different approach which he described as a “distraction strike” on the left side of the mother’s face, using his booted foot.

Luke told the court: “I did kick out at the left side of her face as trained to do. My footwear was a boot but it’s light.”

When asked how he had caused so many different injuries to the mother he said: “I can’t say exactly where and how her injuries were sustained, I can only say what I did.”

The woman told the Guardian she needed plastic surgery following the incident and has been off work for more than a year recovering from her injuries.

Luke accused the mother of grabbing his groin during the attack, which she denied. He said he had acted to protect the child and was concerned that the mother had grabbed her arm and that the child was in danger of falling off the bed and becoming disconnected from the hospital machines.

When asked in court if he had used full force on a mother refusing to leave the hospital, he said: “I wouldn’t say that I used full force but I do remember hitting harder because it had no effect. I used police tactics with good reason that were absolutely necessary. I didn’t go too far. Whenever a police officer uses force you need to be accountable for it.”

Security staff at the hospital who witnessed the incident told the court they were appalled by it. Two police constables who also attended the incident gave evidence for the prosecution. Laura Riley, one of the officers, wept as she described the scene, and the officer Mary Clark described the incident as “just horrific”.

The mother told the Guardian that her daughter had been sick since she was a newborn and she had fought hard ever since to keep her alive; at one point the baby had been on a life-support machine; she had pleaded with doctors not to switch it off.

A Metropolitan police service spokesman confirmed that Luke had been cleared of actual bodily harm and said that a misconduct review would take place.