How do you feel about tapioca? Or semolina? And what does the smell of cabbage do for you? If you’re already feeling nauseous, don’t worry, you are not alone. Adults polled last year by the BBC Good Food magazine revealed that memories of school dinners still haunt them, decades later.

Emotions provoked by tapioca, the number one hate, might alarm Vivianne Buller, but she is made of sterner stuff. She has to be, as she speaks up for school dinners in her role as chair of the Local Authority Caterers Association.

On a recent trip to London to defend her beleaguered members, Ms Buller called in to Harrods to buy a new handbag and pick up some culinary tips.

“There was a bagel bar - now that’s a nice idea. And a fruit smoothie bar.

I’m always on the look-out for new ideas, always trying to think ahead,” says Ms Buller, who is on secondment from Northumberland, where she has been general manager of all county council catering for 12 years.

In Knightsbridge she spotted a panini - “very London, very down-south”. A few trendy cafes in Newcastle might serve these Italianate toasted sandwiches, but they have yet to make it big up north.

But she is open to ideas that are tried and tested in the county where she has worked since 1991, in charge of 800 staff who prepare meals for 210 schools.

Underinvestment is a general problem for local authority caterers. Ms Buller resents those who sneer at school dinners, and defends the service’s often low-paid staff, who dish up 2.5 million lunches every day. Late last year they came under attack from the organic Soil Association, whose report captured headlines by claiming that twice as much was spent on prisoners’ lunches as on pupils’. “The language was puerile and unnecessary,” she says. “And I’ve never found anyone who serves a 31p meal. They must be as rare as hens’ teeth.”

Her members face the same problems as parents, she says, pointing to the less-than wholesome content of most home-provided lunchboxes. “If improving school meals is seen as the solution to reducing adult health problems and the nation’s future health bill, the Government should put its money where its mouth is. The service cannot be seen as an instrument of social policy, child welfare or health reform if it has to continue to operate as a budget-driven commercial trading operation.”

The LACA has been accused of failing to take the lead in improving children’s food, but Ms Buller says it cannot change youngsters’ eating when burger-stuffing adults are letting the side down. Nevertheless, Northumberland does try to improve what pupils eat. Its menus and recipes are analysed by an independent dietician, and it works to government-recommended nutrition guidelines set by the Caroline Walker Trust. Pricing is used to encourage pupils to choose wisely. Chips and pizza, for example, cost far more than the two-course meal.

But, she says, caterers need guidelines on food quality. “There is no baseline. There are guidelines that say I must serve fish once a week, but they don’t say what fish.” In 2001, responsibility for meals was delegated to secondary schools and made an option for primaries. Ms Buller says many heads and governors are making bad decisions. “They need to monitor the food service, check that it meets nutrition standards. A few are having a go, but most have had too little support. And they need to be careful about trying to cut or make money out of the service.” When Ms Buller started in Northumberland, she compared the money parents gave their children for food with the schools’ takings. There was a discrepancy.“About pound;2 million was going up the high street and there are more junk foods there now than when I was a kid,” she says.

She wanted her customers back, and she succeeded. She reckons pound;1.7 million of the pound;2 million has returned to local authority coffers, thanks to the high-school“food courts” she set up. Pupils are offered lots of choice, with a hot bar serving a pound;1.80 lunch; there’s also a cold salad bar. Then there’s the option of a jacket potato or a slice of pizza, although some will just want chips.

Northumberland has been a pioneer of the cashless canteen and the children pay with swipe cards. This shortens queues, impresses them with its “techno” feel, and gives those on free meals a welcome anonymity, as well as allowing staff to check they are actually having lunch. Now about 60 per cent of primary and 75 per cent of middle-school children eat the authority’s dinners.

Despite her many successes it has not all been plain sailing in Northumberland. She may have won back her pound;2 million, which is paying for the installation of the cashless system, but she lost the pound;3 million subsidy the county council had traditionally given for school meals.

Ms Buller wants to strengthen ties between her organisation and headteachers. And she questions the value of squeezing meals service budgets to spend more directly on education. “What’s the point of teaching them if they are going to be dead by 40.”

A special TES supplement, School Food: crunch time for the nation’s children, is published on January 16