Michael Gove heckled at head teachers' conference in Birmingham
The education secretary faced one of the angriest receptions of his three years in office when he appeared before head teachers in Birmingham.
Michael Gove was heckled and jeered at the National Association of Head Teachers conference.
The union passed a no confidence motion in his policies, while president Bernadette Hunter said teachers and pupils had "never had it so bad".
But Mr Gove said he was striving for higher standards in schools.
The education secretary appeared taken aback by the frosty reception as he appeared for the question and answer session on Saturday.
He was told by delegates that head teachers were suffering from stress caused by his policies, by Sats tests and by the prospect of facing tough Ofsted inspections.
In response to the latter, Mr Gove said: "If you think Ofsted is causing you fear I am grateful for your candour, but we are going to have to part company."
At which point, a delegate shouted: "Are you leaving then?"
'Dissolved into tears'
Mr Gove looked visibly ruffled during the session which was repeatedly punctuated by ironic laughter and groans at his responses.
One head teacher, Denise Wells, from Field House Infants school in Derbyshire, said colleagues felt they were living under a culture of "bullying and fear" as they waited for Ofsted inspectors to arrive.
Another, Lesley Wells, from Burton on Trent in Staffordshire, described how one of her school governors with 20 years experience had "dissolved into tears" after a week in which her school dealt with both Sats and an Ofsted visit.
She said as a head teacher she expected to face pressure but she did not think it was right that someone who had given 20 years of voluntary service should.
Mr Gove told delegates he had been "delighted with the warmth and enthusiasm" that had greeted some of the government's education policies.
He admitted that he may have not communicated his vision of the education system well enough, but said that while he had been "chastened by criticism" in the past, there would be no change of course.
"If people find it stressful that I'm demanding higher standards," the education secretary said to audible groans from the hall, "then I'm not going to stop demanding higher standards."
At the end of the session he said: "What I have heard is repeated statements that the profession faces stress, and insufficient evidence about what can be done about it...
"What I haven't heard over the last hour is a determination to be constructive, critical yes, but not constructive."
Russell Hobby, general secretary of the NAHT, told the BBC afterwards it had been "a fairly bruising session".
"It's not because it is a hard job - the job of a head teacher should be tough - but what I think he's failed to pick up on is the short termism of the targets and the constant change, [which] means that people no longer feel that they're doing the job that they came to do, which is to teach children.
"Instead, they're bombarded by a flood of what they see as very poorly thought through initiatives and I think that is where the unhappiness comes from."
Earlier, the NAHT joined the three biggest teaching unions in England and Wales in formally opposing government education policy. It is the first head teachers' union to pass a no confidence motion.
It is critical because it is head teachers who will have to implement the government's school plans.
The stance represents a stepping up of their conflict with ministers and follows on from test boycotts and industrial action.
The union is particularly critical of what it describes as "forced academisation" in which struggling schools are encouraged to convert to become state-funded independent schools instead of remaining part of their local education authority.
The Department for Education argues this is the best way forward for an underperforming school.
But heads say that academy "brokers" employed by the Department for Education (DfE) are using unsavoury methods to push primary schools into opting out of their links with local authorities.
A DfE spokeswoman said: "Academy brokers help us to identify the best possible sponsor to turn around failing schools and ensure pupils are given every chance to fulfil their potential.
"We expect the highest levels of professional conduct from academy brokers and any allegations of misconduct are fully investigated."
The NAHT is the biggest union for head teachers, representing 85% of primary heads and 40% of secondary heads in England, Wales and Northern Ireland.
Stephen Twigg, Labour's shadow education secretary, said: "David Cameron and Michael Gove need to change course. They are damaging school standards by undermining teachers.
"It's no wonder given they are allowing unqualified teachers into our classrooms, teacher morale is at an all time low and 6,000 qualified teachers have left the profession on their watch."