Duchess of Cambridge's uncle admits knocking wife unconscious with 'left hook' after row in taxi

Kate Shilton, prosecuting, told the court how Daniel Shepherd, the couple’s taxi driver, had witnessed the attack on October 13 this year.

She said: "He (Mr Shepherd) describes Mrs Goldsmith slapping her husband to the face. He then describes how Mr Goldsmith punches her hard in the face using a left hook. Mrs Goldsmith has then fallen backwards. He says: 'She appears to be unconscious, she isn't moving'."

After being knocked to the ground Mrs Goldsmith, 47, lay with her eyes closed for around 15 seconds before regaining consciousness and staggering to her feet crying, the court heard.

Following the incident, Goldsmith was described as "panicked and walking in and out of the house, trying to get her to go back in the house".

The court was told that, when Mr Shepherd challenged Goldsmith over his actions - saying to him  "woah mate, you can't do that" - he became aggressive.

Mr Shepherd responded to Goldsmith, saying to him: “What are you going to do, start on me now?”

At this point Mrs Goldsmith asked Mr Shepherd to call the police.

Goldsmith told officers at the police station that he had pushed his wife hard with his left hand, but denied throwing a punch.

Appeared in court wearing black thick-rimmed glasses, a blue three piece suit, an orange tie and a patterned pocket square, Mr Goldsmith spoke to confirm his name, date of birth, address and his nationality as British, before entering his plea.

Shortly before the incident the couple had posted pictures of themselves smiling at a charity auction for the Last Night A DJ Saved My Life Foundation at Home House, a private members' club in central London.

The court heard that Mr Goldsmith, the younger brother of Catherine’s mother Carole Middleton, was apologetic for his actions and was described by police as humbled by what he had done.

He will be sentenced on November 21.

Emma Arbuthnot, the chief magistrate, said: "I am excluding custody and looking at a community order. But I am really looking at how to protect this lady from this man. There may be alcohol issues, I don't know. They were both very drunk."

The court heard that prosecutors are to apply for a restraining order.

Goldsmith, of Marylebone, was granted bail, with the conditions he does not contact his wife, or visit their address.

Mr Goldsmith's behaviour, along with his sometimes colourful lifestyle, has proved to be embarrassing for his royal relatives on more than one occasion .

He was the subject of an expose by the News of the World in 2009, in which he was shown apparently preparing cocaine at his villa in Ibiza and boasting of his connections with the Royal family. He was never charged with any offence.

Mr Goldsmith made his fortune from sports management and IT recruitment and was at one stage estimated to be worth £30million.

The self-made millionaire was brought up with his sister on a council estate in Hounslow, west London, and had initially worked as an IT operator before becoming an entrepreneur.

His father was a painter and decorator from west London and his grandfather worked as a miner in Durham.

When his sister Carole left school, she went on to work for British Airways and Goldsmith was an usher at her wedding when he was 15.

Earlier this year he was a guest at the wedding of his niece, Pippa Middleton to James Matthews.