Mick Brookes says ministers are not being grown up

National Association of Head Teachers general secretary Mick Brookes said there had been "no explanation".

He said ministers were trying "to teach us a lesson" for pulling out of a workload deal.

A government spokesman confirmed the move was deliberate but said it was the NAHT that had "walked away".

Mr Brookes, speaking ahead of the union's annual conference in Harrogate, said Ms Kelly had been asked as early as last Christmas to address delegates but, after delays in responding, had declined.

After that, Schools Minister Lord Adonis had pulled out, having previously agreed to come, he added.

'Not grown-up'

Mr Brookes said: "There's been no explanation, but we think it's to teach us a lesson.

It's unbelievable to me that the government should behave in this way to the people they are relying on to get their agenda through Head teachers' leader Mick Brookes

"The result is this 'we are not going to come and see you' attitude, which is not grown-up government."

He added: "We have quite clearly been snubbed and it's petty."

Tony Blair paid a surprise visit to the NAHT's conference in Cardiff in 2004.

Last year the union withdrew from the government's workload agreement for teachers, designed to give them more time in the classroom and to prepare for lessons.

The NAHT argues there is not enough money to fund the scheme and that head teachers are taking on too much extra work and being left with budget problems.

'Unbelievable'

Mr Brookes said: "We are as desperate as Tony Blair to ensure every child in this country gets the best education.

It should be noted that ministers have attended all other teacher and heads' union conferences that are part of the agreement Department for Education and Skills spokesman

"It's unbelievable to me that the government should behave in this way to the people they are relying on to get their agenda through."

Some "extremely good" officials from the Department for Education and Skills had been told not to attend the conference, Mr Brookes said.

The head of Intake Primary School in Doncaster, South Yorkshire, Liz Paver, said: "I've been doing this job for 13 years and I really want to encourage other people into the profession.

"But the job has changed out of all proportion in that time."

Many head teachers were acting as "social workers", dealing with problems caused by "society getting things wrong", she added.

David Pratt, who runs a primary school in East Sussex, said bureaucracy had increased.

For one trip to York he had had to fill in "42 pages of risk assessments".

Committed

The NAHT estimates the average salary for primary school heads is about �45,000, while those in secondaries get about �70,000.

One union member said that, if he worked in the private sector and had the same level of responsibility, he could quadruple his income.

A DfES spokesman said: "The decision not to attend the NAHT conference was taken some time ago in light of the union's withdrawal from the national agreement.

"It should be noted that ministers have attended all other teacher and heads' union conferences that are part of the agreement.

"It was NAHT not the government that walked away from the social partnership formed by the national agreement.

"We remain committed to working with the profession in real decision-making and making change happen in a true partnership."

The NAHT's conference lasts from Saturday until Monday.