'Whether it is fair or unfair, the tendency is for governing bodies to run around like headless chickens wanting somebody to be a scapegoat so that they can placate those parents who are making their lives a misery,' Mr Hart said.
This year, the prospect of examination league tables has been added to the worsening financial pressures on schools in both the private and public sector.
Some head teachers will have to deal with angry parents whose expectations have been disappointed by last week's A-level results and the GCSE results due out on Thursday.
However, Robert Balchin, chairman of the Grant Maintained Schools Foundation, which is currently preparing guidelines for governing bodies, said: 'I'm glad that heads are under pressure - perhaps the schools will improve.' He argues that head teachers can no longer expect governors to rubber stamp their actions; it must be a partnership. As chief executives, paid pounds 40,000 to pounds 60,000 in the private sector, head teachers should be expected to cope with pressure.
Four head teachers have left independent schools in recent weeks, bringing home the sometimes perilous nature of the job. Governors have shown themselves willing to take swift, uncompromising action if they lose confidence in the head. Helen Williams, High Mistress of St Paul's Girls' School in London, found this to her cost when she alarmed parents and surprised governors with a proposal to restrict pupils to taking seven GCSEs.
Very few head teachers are sacked, according to Mr Hart. But an increasing number opt - under pressure - for early retirement or retirement on grounds of ill health. Two dozen of his members were under suspension and between 25 and 30 a year were 'eased out'.
The recession is making independent school governors jumpy as parents find it harder to meet fees, but grant-maintained schools are under the same pressures to attract a full roll of pupils. So are local authority schools in the Government's rigorous 'sink or swim' regime of local management.
Mr Hart said: 'We need governors who are capable of sifting the wheat from the chaff and standing up to individual parents or groups of parents who are making their lives a misery for reasons that do not hold water.
'Heads are entitled to expect their governing bodies to give them reasonable support.'
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