Some secondary school teachers were guilty of "significantly" over-marking pupils' GCSE English work in a bid to boost results, Ofqual said.
The GCSE exam for children in England is to be replaced by an English Baccalaureate Certificate with the first courses to begin in 2015.
Education Secretary Michael Gove is to unveil details of a major overhaul of GCSE exams marking a return in part to the old O-level system.
Responding to today's report that the government is planning to introduce tests for four-year-olds, a Department for Education spokesperson said:
– department for education spokesperson
We have consulted on our proposed primary school assessment and accountability measures and we are considering our response.
New assessments for children aged four would begin in 2016, according to a report in the Times.
The newspaper says that school children could be assessed between two and six weeks after a starting school in the reception year.
The results could be checked via an external monitoring system, the newspaper reports.
The report says the DfE wants results to be reported as a “scaled score” between 80 and 130 points rather than levels, such as Level 4 or Level 5.
Children aged four will be expected to sit tests within weeks of starting primary school under controversial plans to be announced by the Government, according to the Times (£).
The tests, which are used to establish a “baseline” of each child's ability, would reportedly be moved from seven-year-olds to the beginning of the reception year.
Ministers are understood to want to consult on proposals over the summer and autumn, the report continued.
Ofsted have warned that many of England's most able pupils are being failed by a culture of low expectations.
The report found that in non-selective schools, 65 per cent of pupils who achieved top levels in English and Maths in primary school did not gain an A or A* at GCSE.
The education watchdog called on schools to do more to challenge the minds of the brightest pupils and to consider streaming pupils when they first start secondary school.
ITV News reporter Martha Fairlie reports:
The National Union of Teachers have labelled the evidence behind Ofsted's claims that schools are failing the most academically able as "wrong".
Christine Blower, the General Secretary of the largest teachers' union, said the evidence supporting the claims was "wrong" because Key Stage two test results were never designed as a predictor for future GCSE grades.
The General secretary said young people's aspirations had been deeply harmed by the reduction in the Education Maintenance Allowance, the increase in tuition fees and cuts to schools' career services.
"While schools are never complacent it has to be remembered that Ofsted’s own Annual Report found that 70% of all schools are now good or better. Ofsted has a role to support schools and ensure they are sharing best practice in schools. This report does neither.
"For schools to help and encourage all pupils to reach their full potential we need a curriculum which engages students and is relevant to all the career paths available to young people in the modern workplace".
The Department for Education has called on secondary schools to ensure all pupils fulfil their potential, but insisted the government are making changes to enable students to achieve academically.
– Department for Education spokesman
Sir Michael is right - secondary schools must ensure all their pupils, including their brightest, fulfil their potential.
That's why we are introducing a more demanding and rigorous curriculum, toughening up GCSEs and getting universities involved in A-levels.
The government must provide funding to enable the brightest students to fulfill their potential, according to a leading education charity.
Reacting to a report which suggests the brightest students are being 'let down' by a culture of low expectations, the Sutton Trust, which aims to improve social mobility through education, has warned that the government along with schools need to play their part in improving provisions.
Sir Peter Lampl, chairman of the Sutton Trust said:
"Schools must improve their provision, as Ofsted recommends. But the Government should play its part too by providing funding to trial the most effective ways to enable our brightest young people to fulfil their potential.
"Enabling able students to fulfil their potential goes right to the heart of social mobility, basic fairness and economic efficiency."
– Ofsted's chief Inspector Sir Michael Wilshaw
Too many non-selective schools are failing to nurture scholasticexcellence. While the best of these schools provide excellent opportunities,many of our most able students receive mediocre provision.
Put simply, they are not doing well enough because theirsecondary schools fail to challenge and support them sufficiently from thebeginning.
- Last year nearly two-thirds (65%) around 65,000 students, gained a Level 5 in English and Maths in national curriculum tests but did not get an A* or A grade in these subjects at GCSE.
- Just over a quarter of these students, around 27,000, did not get a grade B in English and maths at GCSE.
- Last year, in a fifth of the 1,649 11 to 18-year-olds not one student gained a minimum of two A grades and a B in at least two subjects preferred by leading Russell Group universities.
A culture of low expectations in many schools has meant that bright pupils are being let down and are failing to gain top grades at GCSE, according to a new Ofsted report.
The report suggests that clever students become used to performing at a lower level because they are in classes where the work is pitched at middle-ranking students.
Chief inspector Sir Michael Wilshaw said it was "shocking" that, in some cases, school leaders and teachers did not even know who their most able children were.