More cash could be found to improve school meals than the pledged £220m, a Government spokeswoman told a school meals conference last week.

Speaking at the Making Sense of the New School Meals Guidelines conference in London, Helen Williams, director of the School Standards Group at the Department for Education and Skills, hinted that the three-year funding plan could be extended if there was proof that it was needed.

"We'd be naïve to think we could achieve everything in the next three years," she said. "But it will be critical to get good evidence from the field. The current position is clear, but in three years' time, who knows?"

School Food Trust member Paul Kelly, who is also corporate affairs director at Compass, called on the industry to gather evidence to support the push for more cash. "Potentially, we need three times as much money, but the trust needs to make the case for more investment - we can't just ask for a blank cheque," he said. "We need to show results can be delivered but that more money is needed."

School meals campaigner Jamie Oliver said: "More money is a must. Catering managers and dinner ladies would feel so much more reassured if there was a long-term cash promise to generate a culture of change."

Kelly said cash could also be found in other parts of the system. "Half a billion pounds is spent [in shops on sweets] every year on the way to and from school. If we could get that money into the system it would be problem solved."

He warned uptake could fall further if parents were asked to fund the whole of the shortfall and if more money didn't come from the Government.

By Tom Bill