Children will have to pay up to 17 per cent more for their school dinners this year compared to last year, a survey has found.

Consumer watchdog Which? also said the quality of school meals needs to improve to encourage more children to eat them and keep costs down after finding that the price is rising in two-thirds of schools across the country in the coming term.

This is leading to concern that it could start to undo the progress made in recent years towards improving children's access to healthier meals.

The research found that parents would rather give their children packed lunches as they believe them to be cheaper, and because their children do not like the food on offer at schools.

Meal prices have risen on average by around 2.5 per cent on last year but some local authorities have increased prices by far more.

School dinners managed by Poole Borough Council are the most expensive in the country at an average of £2.50 this September.

Doncaster Metropolitan Borough Council has increased prices by 17 per cent to between £1.70 and £2 a meal while Lewisham Borough Council has risen by 14 per cent, so that school dinners will cost from £1.40 to £1.60.

The local authority with the biggest increase was Bolton Metropolitan Borough Council at 25 per cent, although its prices still remain the lowest in the country at £1.25.

It is estimated that in order to keep costs down, 55 per cent of students would need to take school meals. However, the research found that just 45 per cent of school pupils in England currently have them.

Richard Lloyd, executive director of Which?, said: "At a time when many people tell Which? their number one concern is rising food prices, it will come as an unwelcome surprise to hard-pressed families to see that some local authorities are increasing their prices by as much as 17 per cent - well above inflation."

Children's access to healthier meals may be restricted after it was revealed school lunch prices will soar by more than 16 per cent as students head back to school.

A survey conducted by Which? found two-thirds of schools will be hiking up the prices in their canteens from September.

The results are likely to spark concern over access to healthy meals for children at school, following years of campaigning over the issue.

David Edwards, director of programmes and partnerships at the School Food Trust said:
"Keeping prices affordable is crucial if we want more families to try school meals, which are typically healthier than the average packed lunch and set children up to learn in the afternoons. We're urging schools to continue investing in good food; helping them to make the lunch experience better so that pupils want to choose school meals, and supporting caterers to operate more efficiently. Ultimately, increasing the number of children eating school meals will mean that schools can spread their costs, reducing the need for subsidy in the longer-term."
The School Food Trust is a national charity advising the government on school meals and children's food. After the trust's report published in 2006 on transforming school food, the government introduced new national legal standards for school lunches.

Schools now have to limit the sale of confectionary, crisps and sugary drinks in their canteens and offer healthy food instead. But the rise in prices have sparked concerns parents will be sending their children to school with packed lunches instead, meaning children may not always get the nutrients they need at lunch.

Celebrity chef Jamie Oliver headed the campaign for healthier school lunches. His Feed Me Better scheme aimed to revolutionise the UK's school dining halls. His drive behind the campaign was: "Children who have been fed better, do better.

"For many kids up and down the country, a school meal is the only proper food they get during the day because their parents weren't taught how to cook so they don't cook fresh food at dinner time. When today's kids get home, it's either ready meals, takeaways or, in the worst cases, nothing at all."