A kitchen porter at a top public school was acquitted today of attempting to poison the pupils' soup.
Maxwell Cook was accused of pouring a bleach-like cleaning product into the carrot and coriander at Stowe School.
But after two-and-half hours' deliberations, a jury of 11 women and one man found him not guilty of attempting to administer poison with intent to injure, aggrieve or annoy.
Cook, 58, slumped back in his seat with a look of relief as the verdict was read out.
A single cry of "yes" was heard from the public gallery.
During the two-and-a-half-day trial at Aylesbury Crown Court in Buckinghamshire, a trainee chef told the jury she had seen Cook in the kitchen lacing the soup with a sanitising destainer.
Louise Samples, 21, said she witnessed the shocking scene at about 3.30pm on March 11 last year after staying behind during the break between shifts to do some studying.
The soup was destined for about 100 pupils and staff at the £27,000-a-year school.
But the presence of the cleaning product in it was detected during a routine tasting and no one was injured.
Prosecutor Robert Spencer-Bernard told the court that if the soup had been eaten, it would have had "detrimental effects".
The toxic liquid added to it is normally used to unblock drains and can cause irritation, vomiting and swelling of the throat.
A spokeswoman for the school said: "We are completely satisfied with all kitchen procedures and there was never a risk of the contaminated soup reaching the dining hall.
"Pupils' safety at Stowe remains paramount."
Cook, from Syresham in Brackley, Northamptonshire, was dismissed from his job at the prestigious school after the incident.
Stowe alumni include business tycoon Sir Richard Branson, Prince Harry's on-off girlfriend Chelsy Davy and jazz great George Melly.
The school said Cook had been sacked for "gross misconduct" after it had carried out its own internal probe into the incident.
And it dismissed the prospect of him being re-hired in the wake of today's verdict.
The spokeswoman said: "The school undertook a full investigation immediately after the soup incident and in accordance with our disciplinary procedures, Maxwell Cook was dismissed for gross misconduct.
"The school has no intention of re-employing him."
During the trial, the jury was not told that Cook was suspected of having a drinking problem.
But while they were out of court, Judge The Lord Parmoor heard that the head chef had been planning to have a word with the kitchen porter about this the day after the cleaning product was found in the soup.
Cook could not have known this however, the court heard during the legal discussion.
Detective Inspector Russ Murden of Aylesbury Criminal Investigation Department said: "I am satisfied with the court's verdict and do not envisage reinvestigating this incident.
"I would like to thank both Stowe School and all witnesses for their assistance during this investigation.
"Thames Valley Police will continue to fully investigate all allegations of foul play and particularly those incidents which affect young and vulnerable people."