They are still grappling with the alphabet, learning nursery rhymes and making toys out of egg cartons.

	Children will be asked to fill in a well-being scale

But now children as young as four will be expected to get in touch with their feelings by filling in questionnaires which ask if they are "optimistic about the future" and "dealing with problems well".

Under guidance being drawn up by the National Institute for Health and Clinical Excellence (Nice), primary schools in England will have a duty to improve children's emotional and psychological well-being.

Schools will be expected to combat factors that are "likely to lead to poor mental health or mental disorders" by introducing programmes to help children make the transition to secondary school, teaching "emotional literacy" and providing specialist counselling services and family therapy.

However, the suggestion that schools should measure happiness has been condemned by headmasters as needless bureaucracy that would divert teachers from teaching.

In a document outlining the draft scope of the guidance, Nice says that a school's success in making its pupils happy will be measured by indicators developed by Warwick and Edinburgh universities, which monitor positive attributes, such as confidence, resilience, attentiveness and the ability to form good relationships.

The "well-being scale" involves putting 14 statements to individuals about their thoughts and feelings and asking them whether they feel like that often, rarely, some of the time, all the time, or never - not unlike the self-help quizzes found in women's magazines. Its use in primary school could see data collected from thousands of pupils, from the age of four to 11, on whether they feel, for example, useful, relaxed and interested in other people.

The burden on primaries to improve pupils' mental health is part of wider drive by the Government to force schools to take responsibility for elements of a child's development that were once considered the domain of -parents and part of a good, traditional upbringing. As revealed by this newspaper, emotional literacy classes, which attempt to teach children how to manage anger and jealousy, and develop empathy and self-motivation, have already been introduced in primary and secondary schools after earlier trials.

The £20 million initiative has supplied schools with a mountain of documents on how to teach emotional intelligence through assemblies, dedicated sessions or discussions in other curriculum areas. It suggests using "worry boxes", where pupils write down their anxieties and post them into a box, and "emotional barometers", which pupils can use to show classmates the strength of their feeling about a subject.

Mick Brookes, the general secretary of the National Association of Head Teachers, said the plan for schools to measure happiness would be a distraction. "Any teacher worth their salt will be able to tell you all about these things, without having to ask pupils how they are feeling against a long checklist. Where there are children who are getting a raw deal at home and have problems, we certainly need to help them, but lumbering teachers with a 'happiness test' is a distraction," he said.

Some academics claim that forcing children to express their emotions has no educational validity and could be counter-productive and even dangerous. "There is no robust, independent evidence that making children and young people talk about their feelings in formal rituals at schools will develop lifelong emotional literacy and well-being," said Kathryn Ecclestone, a professor of education at Oxford Brookes University.

"Inserting a vocabulary of emotional vulnerability, where children are encouraged to feel different or told they have low self-esteem, is likely to encourage the very feelings of depression and hopelessness it is supposed to eradicate. Although ideas about well-being seem benign, they are based on judgemental assumptions about 'appropriate' feelings and how to deal with them. But if you try to challenge this educational bandwagon, you are accused of being in 'emotional denial'."

According to the Office of National Statistics, one in 10 children under the age of 16 have a clinically diagnosed mental disorder. Boys are generally more likely to have mental problems than girls and mental illness is more prevalent among children from disrupted families, those whose parents have no educational qualifications and those from poorer families and -living in disadvantaged areas.