Education Secretary, David Blunkett: determined to transform the culture of education in the country.

Mr Byers told the National Association of Head Teachers annual conference in Eastbourne: "The Government is deadly serious about raising standards and the targets are for real."

In taking this tough line, Mr Byers was responding to a debate at the conference on Wednesday, when delegates supported calls to defy local and national government performance targets.

By 2002, the government wants 75% of 11-year-olds to achieve its required levels for numeracy and 80% for literacy, compared to test figures for 1996, which showed 54% reaching a satisfactory level for maths and 58% for English.

Stephen Byers live on BBC News Online: "Poverty of ambition must end"

Mr Byers said: "Government has a responsibility and it is one which we will discharge. But headteachers have a special responsibility too. We see headteachers as having a key role to play in raising standards.

"Our children do deserve better. This government will not let them down, nor must you. Parents and children expect nothing less."

NAHT's David Hart: Heads should not be forced to set 'unrealistic' targets

The Association's General Secretary, David Hart, said later he had not expected the government to back down over targets.

"You are not going to have 75 and 80% as pledges and manifesto commitments and suddenly back down and say you are going to change them because head teachers are concerned in individual cases about an over-challenging agenda," he said on BBC Radio 4's The World at One.

"What the NAHT said was that heads should not be forced to set targets for individual schools if they regarded the targets as too challenging and unrealistic.

"Frankly I don't really disagree at all with what Stephen Byers said today. We can have a frank argument between head teachers and Government because, broadly speaking, we are working to the same agenda."

Education Minister Stephen Byers: Teachers 'not an easy political hit'

Mr Byers told the programme the target-setting agenda was not "an easy political hit".

He said: "We have staked our political reputation on these challenging and ambitious targets. We will be judged on whether or not we achieve those objectives."