Williams was sacked as chef-patron at his eponymous Michelin-starred restaurant in The Westbury back in October 2019 without any notice period or payment for his notice period, after he entertained friends on a Sunday lunchtime when the restaurant was closed.
Late last year an employment tribunal heard that Williams, who opened the restaurant in 2011, was suspended by his bosses at the hotel for gross misconduct and eventually fired.
However, the chef was ruled to have been dismissed unfairly by the hotel's owners because he had previously been allowed to hold private parties at the restaurant, and had done so on numerous occasions.
Each time Williams brought in his own food and drink, and just used the restaurant as a venue, the tribunal heard.
CCTV footage of the event in question, which took place in July 2019, showed two young guests kicking a soft football in the dining room and taking sugar lumps from bowls laid out for guests. As a result, Williams was issued with disciplinary proceedings and sacked for holding the event without their permission.
However, tribunal Judge Pavel Klimov described the disciplinary procedure as a 'side show' and concluded that the managers were acting because of what hotel owner Azad Cola wanted rather than because Williams was guilty of misconduct.
The tribunal was told that the hotel delayed announcing his dismissal until after the Michelin Guide was published in November, because they feared the restaurant would lose its star once his departure was made public, an outcome that did eventually take place.
Although he found that Williams had been unfairly dismissed, Judge Klimov said that the chef had been partly to blame.
"I find that (his) conduct, in so far as it relates to him allowing children to play in the restaurant with a football and by facilitating it by setting up improvised goals and by not supervising them properly thus allowing them to engage in other activities which could reasonably be seen in that setting as being objectionable (taking sugar cubes with their hands from sugar bowls on the tables laid for breakfast, jumping, wrestling and doing headstands on the sofa-bench) was culpable.
"I find it went beyond the scope of his permission to use the restaurant to host private events, it was disrespectful and caused offence to the owners of the restaurant. The claimant admits that it was 'silly'."
However, Klimov added it was not the fault of the boys.
"I find their behaviour in the restaurant was nothing out of the ordinary and would not have been seen unusual of two young boys at home being slightly bored while their parents entertain guests," he said.
Concluding, Judge Klimov said: "The true reason for (his) dismissal was because the management.. was either directly instructed by Mr Cola to dismiss (him) or they had understood that Mr Cola wished the claimant to be dismissed.
"I find (they) did not have reasonable grounds to believe (he) was guilty of the misconduct. It was known.. that (he) had been using the restaurant for private events and those events involved children playing in the restaurant."
The issue of compensation was set to be determined at a later hearing, the outcome of which is not yet known.
Williams, who was named National Chef of the Year in 2012 and previously also chef-patron at The Wild Rabbit gastropub in the Cotswolds, is understood to still be working with The Pepper Collective on plans to open his own restaurant, most likely in the capital.