The man accused of killing his aunt’s lover alongside his “jealous” uncle has described how the men had fought in the back of his car hours earlier.

Mustafa Alparslan, 21, of Remington Road, Stoke Newington, and Huseyin Akkoyun, 47, of no fixed abode, are accused of strangling and running over 49-year-old Mehmet Degerli.

His body was found in a small car park in Sandringham Road by a passer-by at 1am on June 8, and he was pronounced dead less than an hour later at the scene. Both deny murder.

Alparslan told jurors at Southwark Crown Court today he had been in his pyjamas watching a movie when Akkoyun phoned him on June 7, asking him to drive to his estranged wife Semra Yumak’s home in Sandringham Road.

The mechanical engineering university student had been thinking of going to the gym with a friend, he said.

But Alparslan did not question his uncle’s request because in the Turkish culture children are brought up to “really respect older members of the family” and “if they ask for help we just have to do it”.

He told jurors his uncle had wanted to wait in the car and capture Ms Yumak’s return home on a camcorder.

His intention was to prove his estranged wife had left their four children home alone – giving him ammunition to claim custody of the family.

When Ms Yumak pulled up bumper to bumper with their car, Alparslan recognised his uncle’s close friend Mr Degerli sitting next to his aunt, he said.

It was only later in a police interview – after he was arrested on suspicion of murder – that he realised they had been having an affair, he claimed.

As it happened, Akkoyun fumbled trying to switch on the camcorder – so when Ms Yumak drove off after about 20 seconds, he simply jumped out of the car and ran after her Hyundai, it was said.

After sitting in the car for a few minutes alone, Alparslan said he saw “an opportunity to get away” and go to the gym.

But moments later he claims he saw Degerli and Akkoyun walking towards his car, and Akkoyun told him to drive off after they got in the back seats.

“Could you ever have envisaged how it would end up at that point?” asked his barrister Charles Sheridan.

“No. There was no tension. They were just really quiet,” said Alparslan.

By the time they had reached Downham Road in De Beauvoir, Akkoyun was questioning Mr Degerli over where he had been with Ms Yumak, Alparslan said.

Mr Degerli replied “the mosque”, but when Akkoyun repeated his question he said they had been to “talk about you with your wife”, according to Alparslan.

“They started swearing at each other and about each other’s wives and children,” he said.

“It started to get louder and louder and they jumped on each other. I couldn’t feel my legs or my arms. I felt scared. I felt I had the responsibility to stop them.”

They ignored him when he stopped the car and shouted at them.

He said: “I was on Mehmet’s side so I opened his door. I was saying: ‘Get out. Don’t fight.’ I was expecting my uncle to listen to me more than Mehmet. He knows I don’t like fights. I said: ‘Uncle, stop.’ I saw he had a screen and he wasn’t hearing anything. I ran around to his side and tried to drag him.”

He thought about calling police but couldn’t find his phone, and then decided to drive them back to Sandringham Road so his aunt could “sort it out”.

They “calmed down” on the journey back, and he left them at the corner of Sandringham Road and Cecelia Road where his uncle told him to “go away”.

“I did not lay a hand on either of them two other than to separate them,” he said.

“They were still pushing each other about. They weren’t fighting but there was tension between them. It wasn’t a handshake finish.”

“Would you have ever left home that night if you knew what was to happen?” asked Mr Sheridan.

“Definitely no,” he replied. “That’s why he probably never mentioned it to me. If he knew there was to be a fight I’d have told my mum.”

The trial continues.