They were issued by the Local Government Association (LGA), which said teachers were putting themselves at risk of accusations of child abuse.

Rowie Shaw of the National Association of Head Teachers: "Political corrrectness just one step too far"

Ms Jowell, who is responsible for public health, said the LGA's warning "flies in the face" of teachers' basic instincts.

"Most teachers are used to exercising common sense and doing what is necessary for children in their care," she told a meeting of Labour party activists in London.

"This sun cream announcement flies in the face of the basic human instinct of teachers - to make sure that children are protected from harm.

"I'd like to think that teachers do see it as their job to mop up a grazed knee, soothe a wasp sting or protect a child on a school trip from getting sunburned."

Call for a re-think

Cancer groups had already called for a rethink on the advice, saying that research shows children who suffer severe sunburn are twice as likely to develop skin cancer in later life.

Dr Julia Newton Bishop, of Imperial Cancer Research, said: "Everything must done to convince teachers of the importance of sun protection."

"Whilst I think concerns about child abuse are obviously important, I think it is very regrettable that teachers doing their best to protect young children's skin from the sun should feel prevented from doing what they know to be right by the fear of being accused of child abuse."

Kate Law, of the Cancer Research Campaign, said: "A lot of youngsters are going to do a haphazard, dabbing job. It is a great shame that children can't be helped."

Children under 15 are particularly at risk because they spend three times longer than adults in the open air and young skin burns more easily, she added.

'Teachers are vulnerable'

The LGA is advising teachers to refuse to apply protective lotions to children even if parents ask them to do so.

Ivor Widdison, an education official with the association, said rubbing cream on children's faces, arms and legs would leave teachers open to false accusations which could threaten their careers.

"Teachers are very vulnerable to accusations of physical and sexual abuse," he said.

"Therefore we would counsel strongly against any suggestion that teachers, with or without parental consent, should apply sunscreen products to children in their care."

Mr Widdison has written to the Health Education Authority, calling on the organisation to avoid asking teachers to apply the creams when it publishes new guidelines.

Mixed reaction from unions

A spokeswoman for the National Association of Schoolmasters/Union of Women Teachers said it already advised teachers not to put sun cream on pupils.

"We advise members to be extremely cautious about things like that because of false allegations which can lead to immediate suspension and dismissal," she said.

The head of the Association of Teachers and Lecturers' legal service, Martin Pilkington, said: "We recognise the importance of children being properly protected from the dangers of bright sunlight.

"Quite often, applying sun protection creams or lotions has to be done by teachers, particularly when the children are prone to sunburn. We would advise teachers to ensure that they do so in the presence of another adult."

And the General Secretary of the National Association of Head Teachers, David Hart, joined in criticism of the LGA's recommendation.

"I can understand the spirit it is written in but I do think we are in grave danger of creating a nanny state," he told BBC's Today programme.

"I do think we need to restore what I call some semblance of professional judgment to the teaching profession."