Oxfordshire Labour activists want chocolate and crisps banned from school vending machines - and expect to get their way today.

Celebrity chef Jamie Oliver is fighting to improve school meals

The Witney constituency association has tabled a resolution at the party conference in Brighton calling for a ban on unhealthy snacks from schools.

Education Secretary Ruth Kelly was due to address the conference today and was expected to announce such a move.

But many Oxfordshire schools have already ditched the junk food and believe the Government should be supporting healthy eating in schools rather than imposing bans.

Earlier this year, Ms Kelly pledged extra cash for school meals following a campaign by celebrity chef Jamie Oliver.

The Witney resolution moves: "Conference welcomes the additional £220m from the Government to improve school meals.

"However, it notes research published in the August issue of the Journal of Nutrition showing that dietary fat affects schoolchildren's cognitive functioning.

"Conference notes the public outcry surrounding Jamie Oliver's Feed Me Better campaign in March, and the obesity crisis threatening our young people."

The resolution urges the Government to support the Children's Food Bill, which would prohibit the sale of unhealthy food in school vending machines. It would also introduce minimum nutritional standards for school meals and protect children from aggressive junk food marketing.

Many Oxfordshire schools have already ditched the junk food and are serving healthier food in canteens.

Wheatley Park School in Holton removed all soft drink and confectionary vending machines when it took control of its own catering from the council's in-house catering service last year.

Headteacher Kate Curtis, who is planning to install vending machines selling healthy snacks, disagreed with a ban.

She said: "I think the Government gives us quite enough direction. It would be much more constructive to give schools better support for healthy eating resources and proper buildings for the students to eat in rather than banning particular things.

"Vending machines are a nuisance for schools, because they typically sell products which are not very consistent with healthy eating policies.

She added: "The products do have a higher mark-up and some schools make a profit from them.

"But they can offer a practical way of reducing queues for snacks and drinks."

Alan Lane, headteacher of Cheney School, Headington, Oxford, which has also removed all junk food vending machines, said: "The important thing is that schools adopt a healthy eating policy. Machines can be used to vend healthy snacks, not just fizzy drinks."