A teenager accused of manslaughter has claimed his squash champion stepfather had his hands around his throat when he lashed out at him.

Douglas Herridge said he threw one punch that missed Colin Payne, but then threw a second which caught him on the side of the face.

The single blow proved fatal as 6ft 4in tall Mr Payne slumped to the floor and never recovered.

Asked why he threw the punches, 18-year-old Herridge replied: “Well, he had hold of me around the neck and all I wanted to do was get him off me.”

The teenager said he discovered Mr Payne, 54, had died after leaving the house in Dartford and going to a friend’s home.

“I didn’t really believe that had actually happened,” he told the jury at Maidstone Crown Court. “It is just something I would never think would happen. I couldn’t believe that was the case.”

Softly spoken Herridge was giving evidence after Judge Jeremy Carey told jurors he was no longer facing a murder charge and they would now only have to consider manslaughter.

They have heard how the businessman died as he intervened in a row between the teenager, then 17, and his mother Ina Herridge on November 19 last year.

Mrs Herridge, a 42-year-old NHS risk manager, had refused her son’s request for money because of an incident three days earlier.

The court heard Herridge and Mr Payne, who represented England at squash and won the over-50s British title, had taken hold of each other before the “catastrophic” blow was struck.

It landed on the right side of his head, causing a devastating brain injury.

Herridge, who attended Hextable School near Swanley and Hugh Christie in Tonbridge, said he was very upset when his parents split up in 2011 as he was close to his father.

“It affected my schooling,” he said. “I started crying in the classroom.”

He was also deeply affected by his nan dying in January 2012 and a friend, aged 13, dying from cancer the same year.

“It was very upsetting,” he said. “It had a big effect on me.”

He admitted punching his mother on her arm but did not know what prompted it.

He did not recall putting his hand on her throat for a few seconds, kicking her on the shin or pushing her towards the top of the stairs in other incidents.

“After I punched her on the arm I felt really upset,” he said. “I knew it wasn’t right. I would never do it again.”

He agreed there were occasions when he broke things in the house in Sackville Road, adding: “I must have been frustrated, upset.”

Herridge lived with his father in West Malling for a while before returning to his mother’s home in the summer of 2015.

He started a business course at North Kent College in Dartford but left after three months. He briefly worked at JD Sports, a taxi firm and an air conditioning factory.

Asked by his QC Judith Khan how he got on with Mr Payne, he replied: “We got on very well. I liked him. Sometimes we would have arguments, but nothing serious.”

"We got on very well. I liked him. Sometimes we would have arguments, but nothing serious" - Herridge, about his stepfather

There had not been any violence between them until November 16 after he clashed with his older brother in his bedroom.

He had borrowed his brother’s phone to make a call and was annoyed about “bad images” on it.

“I got into an argument with him about it,” he said. “I ended up pushing him. My mother and Colin came upstairs.”

His mother told him to go downstairs to his bedroom. Mr Payne followed and told him his behaviour was “b***** disgusting”.

“We started arguing,” he said. “I grabbed hold of his shirt and he grabbed hold of me. I was pushed back by Colin. I ended up standing on the bed.

“His t-shirt had ripped. He left. I think he went to see my mum.”

The police were called and he told an officer: “I think we both acted badly.” He stayed overnight at his grandfather’s home.

Three days later on Saturday, November 19, he said he was planning to go out with a friend and went to the study to ask his mother for some money.

Mrs Herridge told him he could not have any and an argument started. He brought up the incident on the previous Wednesday.

“I remember being tearful and upset at the time - the fact that nothing had been dealt with,” he continued. “I think I swore.

“I remember the door flying open and hitting me really hard in the back. I think it was the door handle that hit me in the lower back.

“I kicked the door back. It was done quite hard. It was just a reaction from the door hitting me really hard in the back.

“I guess I was angry and wound up and upset about what me and my mum were already arguing about. I think the door hit Colin.

“I remember Colin’s arms being around my neck. Two hands were around my neck. They were tight. I just remember it being tight around my neck.

“I think I was by the door. I can’t remember having hold of him at all. I honestly can’t remember anything being said before that.

“I remember throwing two punches. The first one missed and the second one connected with the right side of his face. I didn’t throw any further punches.”

Miss Khan pointed out that medical evidence showed the blow connected with the left side of Mr Payne’s face.

Asked if he recalled how much force he used, Herridge said: “Thinking back, I don’t know how much force was used. I remember Colin letting go.

“When I struck the second blow I was scared. I didn’t know what was going to happen. I had to defend myself. I remember him going slowly towards the ground.

“When I left the room I think he was going to the ground. I didn’t know how badly hurt he was. I thought he was just a bit dizzy.

“I ran out of the room to my bedroom to get my key and put my shoes on.”

He went straight out of the house to his friend Arry's home.

Questioned by prosecutor Richard Hearnden, the teenager denied resorting to violence when angry or upset.

He said of Mr Payne: “I have always liked him.”

He could not remember how hard Mr Payne held him around the neck or if he was choking or having trouble breathing.

After he threw the punch that missed, he claimed, the grip on his throat tightened.

“I remember his eyes staring wide at me,” he added.

He could not recall his mother screaming to her partner: “Colin, Colin, stay with me.”

Herridge, of Sackville Road, Dartford, denies manslaughter.

The trial continues.