A man jointly accused of murder has told a jury of the moment he "thought the worst"... that his friend was killing Natalie Jarvis in Swanley Village.

Speaking from the witness box at Maidstone Crown Court, Thomas Fuller explained how he climbed out of his hiding place in Adam Whelehan's car boot to see the pair standing with their hands on each other's shoulders.

As they moved farther down Button Street Fuller said he thought he heard Natalie "ordering" Whelehan to "get off".

Asked by his barrister Jonathan Higgs QC what he thought was happening, Fuller replied: "Because I couldn't see no weapons and there was no talk of a knife previously, I didn't know at first.

"But as they went round the corner I turned the car round and thought the worst."

Asked by Mr Higgs to explain what he meant, Fuller continued: "Adam was killing Natalie."

Whelehan, 23, of Roseberry Avenue, Sidcup, and Fuller, also 23, of Oakley Drive, Eltham, south east London, both deny murder.

It is alleged Whelehan hatched a plot to kill Natalie, whom he believed was pregnant, because he saw it as the only way of ending the relationship. He claims, however, that he acted in lawful self-defence.

Fuller is alleged to have "encouraged and played a part in" the murder plot.

He told the court he first heard Natalie saying "Get off me Adam" while he was still in the Renault Clio boot. He said he was hiding in the boot because he wanted to hear whether Natalie "slagged off" him and his deceased father.

Floral tributes at the spot where Natalie Jarvis died in Swanley Village

He described her as sounding "playful and jokey" the first couple of times she said it, but then became more serious.

Fuller added that their voices "drifted away" and he "froze" for a few seconds in the boot. However, he then released the door, climbed out and got into the driver's seat.

He told the court he intended to drive the car down the road towards the couple but then, having carried out a three-point turn in a nearby industrial estate, remained where he was.

"I didn't want to go down there and be involved in what was happening, what I thought was happening," he said.

Fuller continued to tell the jury amid a packed courtroom that Whelehan came jogging back and got into the passenger seat.

He noticed blood on his face and tracksuit bottoms.

"I said to him: 'What's happened?' and he said: 'I didn't know my own strength. I pushed her into a bush.'

"I think I may have given him a funny look because of the blood and he showed me his hand and said: 'I cut my hand when I pushed her.' His hand was bleeding quite badly."

Jokes about "Adam doing Natalie" were "flying around" among Whelehan, Fuller and another friend just over an hour before she was fatally stabbed, the court also heard.

But Fuller dismissed the remarks made as they queued for food in McDonald's as nothing more than "banter".

"I can't remember exactly what was said but it was all taken with a pinch of salt," he explained. "Everyone was laughing about it and nothing was taken seriously.

"I thought nothing of it. I just thought it was usual banter."

Fuller claimed the first time his friend mentioned wanting to kill Natalie was when he told Fuller she was pregnant.

He said he noticed Whelehan's personality had changed and he was "down in the dumps".

But Fuller told the court that although Whelehan had spoken on a number of occasions about killing Natalie, he did not take any of his remarks seriously.

"I have known Adam since I was five years old and I have never seen him violent. I just thought he was trying to act like a hardman."

Fuller agreed with his barrister that his texts to Whelehan could be interpreted to suggest he was "going along with the idea" or offering encouragement.

But when asked why he had not responded differently, Fuller explained: "Because I have known Adam for so long this is the first incident he has come across like this and I just never believed Adam would do this."

"i said to him: 'what's happened?' and he said: 'i didn't know my own strength. i pushed her into a bush'" – thomas fuller, in evidence

Fuller himself had only met Natalie on one occasion about six weeks before her death.

He told the court he could not recall whether he or Whelehan gave Natalie the nickname, JC, in reference to actor James Corden, but admitted he didn't feel proud about the way he spoke about her in text messages.

Fuller also sent Blackberry messages to another friend, Bridie McCann, while he was still in the car boot.

They included one in which he stated "He's done it, he's f***ing done it". Asked by Mr Higgs what he meant by the word "it", Fuller explained to the jury: "Stabbing Natalie, killing Natalie."

Fuller also told the jury that Whelehan told another friend he had "slit Natalie's throat" within minutes of the stabbing.

The pair met up with Matthew Woods in Sidcup after leaving the alleged murder scene.

"I was shocked to hear what he had said, that he had slit Natalie's throat. Matt was just calm and it didn't seem to register with him. He didn't react to it."

Asked how he himself reacted to Whelehan's remark, Fuller continued: "Because of the way Matt had reacted I didn't know whether to believe it or not.

"Deep down I think I knew it had happened but the way Matt was reacting it didn't seem true. Adam was just quiet. He wasn't behaving strangely, he was just really quiet.

"If you asked him a question it would just be a one-word answer."

Fuller eventually drove Whelehan to Bexleyheath police station in the early hours of the morning.

The trial continues.