Increasing numbers of primary schools could be at risk of being considered under-performing under new Government plans to raise the floor target on achievement.
From next year, primaries in England must ensure that at least 65% of their 11-year-old pupils score Level 4 - the standard expected of the age group - in English and maths, and meet national progress measures, Schools Minister David Laws announced.
Under the current system, schools are expected to ensure that 60% of pupils meet this benchmark.
Schools that fail to meet the target, particularly those with a long history of under-performance, face being taken over and turned into a sponsored academy.
The Department for Education (DfE) said that sponsored academies are the best way to turn around weak schools.
Official figures show that in 2011, 1,310 primaries in England were below the 60% standard, and this fell to 476 schools last year.
The fall showed that headteachers, teachers and pupils respond to higher floor standards by raising their achievement, the DfE insisted.
It said that if the floor target had been 65% in 2011, 1,915 schools would have fallen below it, with 866 under it last year.
Mr Laws said: "We must ensure that a far higher proportion of pupils are 'secondary ready' by the end of their primary school. This will allow them not simply to cope, but thrive, when presented with the challenges and opportunities of secondary school. We have already introduced tougher floor standards to drive up standards - and this has been a genuine success. The vast majority of schools have responded to the higher floor by raising performance. As a result, we will raise the floor standard again, from next year."
Shadow education secretary Stephen Twigg said: "Improving standards in primary schools is a Labour priority. We would address the root causes, not just how we measure standards. David Cameron's record is one of letting young people down. He has cut back on catch-up tuition programmes in English and maths, and thousands of teachers are leaving the profession. With the biggest cuts to education spending since the 1950s and the pupil premium merely plugging the gap in schools' budgets, too many pupils aren't getting the support they need under David Cameron."