Parents should be prepared to accept a fall in the number of pupils getting top GCSE and A-level grades, Michael Gove warned yesterday.
The Government's crackdown on grade inflation will mean fewer As and A*s being handed out in an attempt to return to realistic results, the Education Secretary said.
Mr Gove argued that this was a price worth paying for an exam system that commands respect among universities and parents.
In an interview yesterday, he said grade inflation 'discredits the integrity of our education system' and GCSEs, A-levels and degrees must get 'tougher'.
'If that means fewer passes, then that's something we'll have to accept, but I want to ensure that as well as exams being tougher, schools work harder,' he said.
'What I hope we will see is our exams are once again trusted across the globe and our children are among the best in the world.'
Mr Gove said he would not emulate his Labour predecessors and pat himself on the back if exam results were to go up each year.
He said: 'Unfortunately, the real achievements of children on the ground became debased and devalued because Labour education secretaries sounded like Soviet commissars praising the tractor production figures when we know that those exams were not the rock-solid measures of achievement that children deserve.'
Mr Gove added: 'You've got to tell the truth about these things. When people see that pass rates have improved at this level, they know that while schools have improved, they haven't improved at that rate.
'It discredits the integrity of our education system.'
Mr Gove also said that improving the UK's place in international school league tables would take ten years to achieve. In 2009, England slipped to 25th for reading, 25th for maths and 16th for science.
Mr Gove spoke out as he prepared to outline new plans to improve discipline.
Head teachers will no longer need to give 24 hours' written notice for detentions outside school hours from today.
Schools will get new powers to keep unruly pupils behind after lessons as part of a drive to restore order in the classroom. These 'no notice' detentions are one of the key elements of the Education Act 2011, which aims to help teachers maintain discipline in the classroom.
Other changes will follow in the coming months, including extended powers for teachers to search pupils for items 'that are going to be used to cause harm or break the law'.
Teachers will also be granted anonymity when accused by pupils, and independent appeals panels for exclusions are being overhauled so that they will no longer be able to reinstate pupils who have committed serious offences.
The Coalition has also laid down regulations which, subject to Parliamentary approval, will mean that teachers will be able to search pupils for tobacco and cigarette papers, pornographic images and fireworks, without their consent.
Charlie Taylor, the Government's expert adviser on school behaviour, said yesterday: 'Without good behaviour, teachers can't teach and pupils can't learn. Teachers need to have the right powers at their disposal to use if they wish.'