A gardener killed his lover by repeatedly bashing her in the face with a rock because he claimed she insulted his manhood, a court heard.

An emotional Peter Ling, 50, from Wallington, told the Old Bailey that horticultural lecturer Lynda Casey, 54, from Coulsdon, had told him he was not “big enough down below” as he tried to find out how he compared to her other lovers.

Married Mr Ling is accused of murdering his lover Mrs Casey after finding out she was seeing another man.

Giving evidence Mr Ling said: “She said I wasn't big enough for her. It was so flippant, she was gloating and I just completely lost it.

"I picked up a piece of chalk or something and I just hit her instantaneously. She fell down and I hit her again. I wasn't conscious of it, I just kept hitting.

"I don't remember stopping. She made a last few noises but I could see she was dead. I couldn't believe I'd done such a thing. I didn't want to kill her. It was like a pressure cooker or something waiting to go off when she said that comment.”

He had previously told the court he had taken Mrs Casey to Banstead woods on August 8 last year to talk about his future with her.

The couple walked for about 15 minutes before having sex in a copse near where the 54-year-old’s decomposed body was found by sniffer dogs four days later.

The defendant had told the court, when cross-examined by his lawyer Ignatius Hughes QC, that he had become “physical” when they were in the woods.

Mr Ling admitted that he had “pushed Mrs Casey against a fence” in order to get her to walk to a copse, or clearing, away from the main path through the woods.

He said: “It was persuasive but inappropriate. But she had driven me to it through her lack of communication.”

It was at the point, the defendant claimed that he told Mrs Casey he was considering leaving his wife and they allegedly had sex.

Mr Ling told John Coffey QC, prosecuting, that it was about an hour between the couple having sex and him hitting her with a “piece of chalk”.

Mr Coffey said: “So in an hour you had gone from being a pair of tender lovers to you taking her life? What was said in that hour?”

Mr Ling sat in silence and did not answer, prompting Judge Giles Forrester to intervene.

Judge Forrester said: “Mr Ling, your defence rests on provocation being proven and counsel wants to know what was said in that hour?”

Mr Ling belatedly said: “I was trying to draw out of her how I compared with previous lovers.”

Mr Coffey replied: “You’re making this up? This isn’t what happened is it.”

Mr Ling, who denies murder, said: “No.”

The trial continues