A school has stopped its tuck shop from selling sweets and fizzy drinks because it believes they over-stimulate the children.

Seaford College, a co-ed boarding school in West Sussex, suspects that break-time snacks high in artificial flavourings and additives were affecting its pupils' concentration.

The headmaster, Toby Mullins, said pressure for a change had come from the teachers.

The jury was out on whether it had worked, but three weeks into term the anecdotal evidence was that it had.

"The school has a very broad intake in terms of ability and you need to have them focused in class as quickly and for as long as possible," he said.

Alternatives

"A lot of the teachers had said to me that when the pupils came back from their break having had a bag of pick 'n' mix it took quite a long time to get them settled."

He was sceptical, but while looking after some of the more hyperactive children on a school choir trip to the United States - where they did not have such sweets - he was convinced they were easier to handle.

The proposed ban had gone down well with parents, he said, so since the start of term the tuck shop has been stocking mainly cereal bars, sparkling fruit drinks and fresh rolls.

The students had not complained, Mr Mullins said.

"If we'd said, 'Right, we're going to get rid of all the opportunities for you to eat any food at all between meals' I think they would have gone off the end of the pier.

"But they can get a bacon, lettuce and tomato roll or whatever at break times and I think to the students that's just as good. I don't think they mind as long as they're filling up on something."

Takings had gone up by 25%, he said - although that was mainly because the individual items were more expensive.

Controversial

Mr Mullins said there was no proof that pupils' behaviour had improved, but the anecdotal evidence was that classrooms were calmer.

"We have had three weeks now and the teachers and certainly the lady who runs the tuck shop are convinced it has had a beneficial effect."

The possible health risks of food additives are controversial.

All additives in the UK and Europe are controlled by law, and can only be used following stringent tests and approval by an independent committee of scientists and medical experts.

But some scientists have linked additives - particularly tartrazine or E102 - to hyperactivity in children and other problems.