Education secretary Michael Gove was accused of being 'unqualified to do the job' as he prepared to announce new targets that could put an extra 20 of the region's high schools in danger of government intervention.

Norfolk headteachers rounded on Mr Gove for the plan to raise the minimum acceptable results at GCSE - with one calling him a 'headline grabber'.

It has been widely trailed that he will lift the floor target from the current 35pc of students getting at least five A*-C GCSEs including English and maths to 50pc by 2015.

Seven schools in the EDP area fall below 35pc on the basis of their 2010 GCSE results. That figure would leap to 27 if Mr Gove's plan became policy.

The education secretary, who has triggered anger in many school staff-rooms with the constant stream of new ideas since he took office a year ago, said the stiffer target would end a low expectations culture in some schools.

But some Norfolk headteachers reacted with fury.

Melinda Derry, headteacher at Stalham High, where 40pc of students hit the GCSE target in 2010, said: 'Our expectation is that we are on course to hit the new target, so we don't have an issue with that.

'But what happens to the 50pc of pupils for whom an academic curriculum is not the right curriculum? To say that only academic qualifications are suitable writes off half of the youngsters in schools.'

She added: 'Mr Gove's ideas seem to be entirely arbitrary. We haven't got any clear guidance on vocational education, and it feels as though he is just headline grabbing. The figure is not based on any good sense at all.

'He has no intellectual credibility, nor any intellectual background or qualifications to do this.'

Rob Anthony, associate headteacher at The Hewett School in Norwich, where 28pc of students reached the benchmark in 2010, said: 'The government doesn't seem to take any account of where a school is located and who goes to that school.

'If all things were equal, every school should get 50pc, but all things are not equal.

'We think we will be in a position to meet the target, but that's because the ability profile of our students is rising. But you do have cohorts where you know that no school would be able to get near 50pc.'

He added: 'It seems entirely wrong to punish a school which is doing its best to achieve the impossible.'

Nicole McCartney, principal of Ormiston Venture Academy in Gorleston, which is expecting to improve from 36pc in 2010 to at least 50pc this year, had a different view.

She said: 'I think maths and English are crucial skills. And even if you are looking at 50pc, you are still saying that half of children won't have those GCSEs, which is a worry.

'But we are working in difficult circumstances and are hoping to hit that target in the first year of operation. I think expectations must be raised.'

She added that a 'conversation' needed to be held about schools that needed support to reach the target. She said: 'Increased expectations and decreased budgets do not go well together. You have to have the resources to enable things to improve.'

Last year 780 English secondary schools fell short of the 50pc benchmark. But the target does also include the 'value-added' progress measure between age 11 and 16.

Schools that fall below the floor targets risk being taken over by a successful neighbouring academy, a policy introduced by the last Labour government.

In a speech that he will make in Birmingham today, Mr Gove will argue Britain and the rest of Europe need to accelerate the pace of educational improvement to compete with successful economies, especially in Asia.

He is expected to propose raising the benchmark to 40pc in the 2012/13 academic year and to 50pc by 2015.

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