A Chessington man who claims his son was slapped by ambulance staff and held down by six police officers has made a formal complaint against the emergency services.

James Anderson, of Willcocks Close, has slammed the "brutality" of the emergency services after his 18-year-old son Alexander Wright was attacked during a night out.

Mr Anderson said his son was in a distressed state when he arrived at Kingston hospital on April 26 and was then hit by ambulance staff and knelt on by six police officers while awaiting a Cat scan for a possible bleed on the brain.

Mr Anderson, a driving instructor, said Alexander, a former Epsom College pupil, had earlier staggered home on April 26 after being attacked and hit over the head near Red Lion Road in Tolworth.

"He was clearly concussed and in shock and was vomiting," he said.

"He was delirious, he didn't know where he was or who I was and yes, he was agitated and was shouting out, but he had just been attacked and didn't deserve this.

"I have the utmost respect for the emergency services and I understand they have to use reasonable force but this was not reasonable - it was frightening."

Mr Anderson, who was threatened with arrest for trying to intervene, said the alleged assault left Alexander with visible cuts, bruises and a black eye.

He has now put in a formal complaint against Kingston police and London Ambulance Service (LAS).

"He had his arms bent under him the wrong way and he was screaming when the officers were kneeling on him," he said.

"It was very upsetting."

Alexander was discharged on April 28 after treatment for a head injury which has left him with short-term memory loss.

Mr Anderson said it was "appalling" that nobody had been to take Alexander's statement about the initial attack in Tolworth.

"This was not a Saturday night brawl the police and ambulance had arrived at - it was a kid with an injury," he said.

"Where is the professionalism of the authorities? He was a patient not a prisoner."

Kingston police and the LAS confirmed they did attend an incident involving Mr Wright.

A spokeswoman for Kingston police said a complaint has been made which is now subject to a "professional standards investigation" and they could not pass further comment until this was resolved.

An LAS spokeswoman said: "This incident is the subject of a formal complaint and it would be inappropriate to comment further pending the outcome of an internal investigation."