Liz Paver, president of the National Association of Headteachers, cautioned the Prime Minister and his education team to consult widely, listen carefully. Any change should be at “a steady pace in bite-sized pieces”.

“Even the abolition of the disgraceful nursery voucher scheme must be carefully planned so that current school budgets are not adversely affected, ” she said.

Mrs Paver used her presidential speech at the union’s centenary conference this week to warn David Blunkett, the Education and Employment Secretary, not to take teachers for granted and to outline priorities in primary, secondary and special schools for the new Government .

Elsewhere in their annual conference this week, headteachers were due to warn Mr Blunkett that they could not deliver his literacy and numeracy targets because the curriculum was too broad and distracted them from the basics.

He has said his policy will be judged on meeting the Government targets of 80 per cent of 11-year-olds reaching an appropriate standard of reading and 75 per cent an appropriate standard of numeracy by the end of Labour’s first term.

Mrs Paver, head of Intake primary school in Doncaster, said curriculum reform in neither key stage 1 nor key stage 2 was right yet. She insisted that overload and inappropriate placement of some material had to be addressed.

She also wants non-contact time to be an entitlement for every primary school teacher, as well as a reduction in class size.

In secondaries, Mrs Paver said the 14-19 curriculum had to recognise that the varied routes had parity of esteem, and she called for proactive strategies for dealing with disaffected pupils.

Special schools should be given “adequate” resources to enable every local authority to implement fully the SEN code of practice.

Mrs Paver said schools, which were responsible for children for a maximum of seven hours a day could not be responsible for the values and morals which influenced them outside the classroom.

“For some pupils we can only mitigate the damage done during these hours - provide an ‘oasis’ of care, love, forgiveness, within a quality environment, underpinned by fair and consistent discipline, and have the courage and commitment of our founder members to provide the highest quality educational provision for all.

“We have coped too long, been held to ransom because of the concern we have for our pupils and our determination not to let their education suffer because of ill-conceived and underfunded initiatives.”

She attacked as scandalous underfunding in schools, citing cases of headteachers busking around the country in their holidays to raise funds for staff, and begging or buying new cars in order to raffle them off to get cash for redecoration. “Who would want to lead a school in these circumstances? A poisoned chalice doesn’t even begin to describe it.”

But Mrs Paver saved some of her strongest criticism for the Office for Standards in Education and Chris Woodhead, the chief inspector and to some the profession’s bete noire. She claimed he had brought shame and a lack of confidence to the office: “His army of clipboard-carrying, ticklist experts has brought an unprecedented fear and uncertainty into our schools, because of their negative agenda. They are out to find failure - not to acclaim success. ”

Mrs Paver said that, like both the Prime Minister and Mr Blunkett, heads’ aim was to raise the achievements of all pupils. And in a message to the Labour leadership she said: “We are ready and willing to play our part in the ‘partnership with the profession’ to which you have declared yourselves committed, but if it is really education, education, education, new money will be absolutely essential.

“We demand your support: you promised your support, now deliver your support. ”