By Katherine Sellgren BBC News Online education staff

Teachers at a London school say a ban on junk foods and fizzy drinks has dramatically improved pupils' behaviour.

New End Primary School in Hampstead has banned children from bringing in sweets, crisps, chocolate, fruit bars, fruit juices and fizzy drinks in their lunch boxes.

The school wants to promote healthy eating

The only drink allowed now is water.

The new rules have only been in place since September, but head teacher Pam Fitzpatrick said the children were noticeably better behaved.

"The children have been very positive about it and they are much calmer in the afternoons," said Mrs Fitzpatrick.

Healthy eating

The new regime is part of the school's aim to educate pupils about healthy eating habits.

"We really didn't realise how many additives there are in things which are advertised as being healthy, like some fruit bars," said Mrs Fitzpatrick.

The water-only rule also applies to pupils who have school dinners, but foods which contain additives have not been banned in the canteen because the menu is in the hands of the local education authority's contractors.

But there is always a salad and fruit option on offer, Mrs Fitzpatrick stressed.

Mrs Fitzpatrick has also noticed how much tidier the school has been since the start of the autumn term.

"When children bring in all these junk foods, you get a lot of litter as a result - crisp packets and so on.

"Also, in the summer, when youngsters bring in fruit juices and put the cartons in the playground bins, you get a lot of wasps which can be distressing for some."

Mrs Fitzpatrick said parents had overwhelmingly backed the idea.

"Parents have actually been very grateful - I did think I might get a barrage of opposition, but many of them have said it makes life easier at home because the children are continuing to drink water there."

Given its success, the school is now likely to make the ban a permanent fixture.