Seven-year-old Jaye Adlam has fallen foul of a "no fizzy drinks" rule at Shipton Bellinger primary, near Andover - for bringing in sparkling mineral water with his packed lunch.
His mother Debbie, a 34-year-old recruitment consultant, claims headteacher Derek Atkinson said the rule was necessary because fizzy drinks make the children burp.
Mr Atkinson denied using the b-word, but said "anti-social effects" (ie wind) can result from running around the playground after a bottle of pop. This is one of the school's justifications for the ban - the others being the potential for mess and spillage and the dubious health value of most fizzy drinks.
He concedes the latter does not apply to carbonated water, but that the school's rules are quite clear. The dinner ladies are primed to discourage children from bringing in "inappropriate" items in their lunchbox.
"We have a no fizzy drinks rule published in our brochure, and it is policy in many Hampshire schools. The dinner ladies said 'Jaye, you can have that today but don't bring it tomorrow.' "We have a superb rapport with parents. This is the exception. If I start bending the rules for one, we will have all sorts of situations arise," he said.
Ms Adlam, who sends Jaye off with a lunchbox of healthy salad, fruit and vegetables, is unhappy that the school does not distinguish between carbonated water and other fizzy drinks.
"The whole thing is preposterous," she said. "The dinner ladies told Jaye it was unhealthy. I actually had to sit him down and explain that water isn't unhealthy. Besides that, I would have thought the school had more pressing problems than the odd burp from a young lad."
The school, surprised by the level of local media interest in the story, is hoping things will now go flat.