A livid Jamie Oliver vowed yesterday that "heads would roll" after finding out one of his restaurants has been serving eggs from battery chickens.
The news is a major embarrassment for the chef, just days after his campaigning TV show Jamie's Fowl Dinners revealed the grim reality of battery hen egg production.
And the blow itself couldn't have arrived with worse timing - a chicken farmer was given the battery egg at Fifteen Cornwall while the primetime show was shown on Channel 4 last Friday.
The farmer used his mobile to take pictures while being given a tour of the restaurant kitchen by a waiter.
Jamie told the Mirror yesterday: "I am speechless. We have cast iron rules on what any chef can and cannot buy in all Fifteens.
"I can't stop thinking it seems a coincidence this one-off has happened the week my programme airs. I've never been so disappointed. Heads will roll."
Jamie is trustee of the 15 Foundation charity and founder of all four Fifteen restaurants.
It has emerged Fifteen Cornwall bought 360 battery chicken eggs when a regular supplier of free range eggs let them down.
The farmer who found the egg was eating with 12 pals - including some battery chicken farmers - who were attending a wedding in the area.
A source said: "The farmer asked to see an egg. A waiter brought him an egg but the customer said 'This is a battery chicken egg'.
"The staff were shocked a chef could make such a stupid mistake - everyone is upset and the remaining battery eggs were thrown away.
People at the restaurant feel really strongly about free range eggs and thinks Jamie's campaign is brilliant.
"I feel somebody should be sacked over this, but I don't know if it will happen."
Restaurant chief executive Dave Meneer said: "We can only apologise and have taken steps to ensure this cannot happen again.
"We are very sorry for any embarrassment this may have caused Jamie. I'm sure it is the last thing he needed.
"I was at home watching Jamie on TV when this happened - the timing was amazing, you just couldn't have written the script. I barely believed it when I was told - but it's a fair cop.
"We were too complacent and should have checked the source. I could go throwing my weight around firing people, but I don't see where that gets you.
"I've got a cracking team of chefs and I need them all, but I have been reading the riot act because this was fundamental to how we do business."
Chefs use around 800 eggs a week at Fifteen Cornwall, which has served 120,000 diners since opening in Watergate Bay, Newquay, in May 2006. Some meals there cost £50 a head.
The restaurant employs 16 trainee chefs from disadvantaged backgrounds and another 19 youngsters are in college waiting to take up jobs.
Fifteen Cornwall boasts on its website how its eggs come from Clarence Court in nearby Liskeard.
It says: "The hens at Clarence Court are from old-fashioned breeds such as the Old Cotswold Legbar and the Burford Brown.
"Allowed to roam freely and given a totally natural diet, the hens produce seriously good eggs."
GO TO WORKThe average hen lays 257 eggs a year
Britons eat nearly 10billion eggs a year; that's 26million every day
EGGHEADSWhite-shell eggs come from hens with white feathers and white ear lobes, brown eggs are produced by red hens with red lobes