The Court of Appeal has upheld a damages award made to a young person with autism who was restrained by police after jumping into a swimming pool fully-clothed.

Last year, the High Court found that Metropolitan Police officers subjected the young person – then aged 16 and who has autism, learning disabilities and epilepsy – to assault and battery, unlawful disability discrimination, false imprisonment and multiple breaches of the Human Rights Act by forcing him into handcuffs and leg restraints.

The incident occurred during a school trip to Acton Swimming Baths in West London on September 23, 2008, after the young person, known only as ZH, who cannot communicate with speech, jumped into the pool fully clothed. While he was lifted out of the pool by lifeguards, the police, without consulting with his carers, took hold of his arms before handcuffs and leg restraints were applied. By then agitated and distressed, ZH was placed in a cage in the rear of a police van until calmed by carers and allowed to leave with them.

ZH, who was said to suffered moderate post-traumatic stress disorder as a result of the incident, was awarded £28,250 in damages.

However, the Metropolitan Police appealed the decision. At the appeal court, Anne Studd QC, representing the police, said the judge at the original trial had failed to understand “the bigger policing picture” or to build in any operational discretion when officers genuinely believed they were in an emergency situation that required them to act at once.

But Lord Dyson, sitting with 2 other judges, dismissed the appeal, saying “nothing could justify the manner in which the police restrained ZH”.

A statement from the Metropolitan Police said that its officers are frequently called by the public and other agencies to incidents involving people with mental health issues or learning difficulties. “We are called when others feel they cannot manage without our assistance. Our officers are required to make decisions affecting people with such impairments in difficult, on occasions fast moving and potentially life-threatening or harm-causing situations.

“We appealed because we believed that the County Court judgement would make it very difficult for our officers to respond in such situations, that this could fetter their operational discretion and wished for greater clarity in relation to what officers must do in operational situations.

“[This] judgement… will help us to examine our policies and develop our training and processes.”

Meanwhile, Amanda Batten, director of external affairs at the National Autistic Society, renewed the charity’s call for autism training to be made mandatory for police officers: “The Court of Appeal has confirmed that in this case the police lacked the necessary understanding and flexibility to adapt to a person’s autism and subjected a vulnerable young person to inhuman and degrading treatment.

“Autism training is not routinely provided as part of police training in the UK despite the fact that the condition affects around 1 in 100 people.

“People with disabilities look to the police to protect them and it’s vital that their needs and behaviours are understood and accounted for. Autism awareness and strategies should be standard in police training to ensure that policemen and women understand the needs of this section of society and can act appropriately.

“A better understanding of autism by the police will go a long way towards ensuring that disturbing cases like this never happen again.”