Schools across England face a growing sense of crisis because the Government has not dealt with a rise in the number of teachers quitting, MPs have said.
The Commons Public Accounts Committee (PAC) criticised the Department for Education (DfE), saying it had "failed to get a grip" on the retention of teachers.
The report said it was particularly worrying that the number of secondary school teachers has been falling since 2010.
Schools only managed to fill about half of vacant posts in 2015/16 with qualified teachers who had the experience and expertise required, according to the report.
The PAC said the Government had got the balance wrong by spending £555 million a year training new teachers, and just £36 million on retaining and developing teachers.
MPs called on the Government to move to end wide variations in the quality of teaching across the country.
The report said that in the Midlands and the north of England more than 20% of pupils were in secondary schools rated as "requires improvement or inadequate for teaching, learning and assessment".
The report stated: "The quality of teaching and the level of teaching vacancies vary significantly across the country.
"However, the department does not seem to understand the reasons for the variation or the different challenges that schools in different regions face.
"The failure of the department to get to grips with the number of teachers leaving puts additional pressure on schools faced with rising numbers of children needing a school place and the teachers to teach them."
While the overall number of teachers rose by 15,500 between November 2010 and November 2016, secondary school posts dropped by 10,800 in the same period.
MPs expressed concern as DfE forecasts show secondary school pupil numbers will increase by 540,000, almost 20%, between 2017 and 2025.
The number of teachers leaving the profession for non-retirement reasons increased from 22,260, or 6%, in 2011 to 34,910, 8.1%, in 2016.
The PAC said pressures of workload was a big factor in teachers leaving the profession, as well as living costs.
The report called on the Government to look at whether adequately funded initiatives could help teachers with housing costs in expensive property areas.
PAC chairwoman Meg Hillier said: "A crisis is brewing in English classrooms but Government action to address it has been sluggish and incoherent.
"It should have been clear to senior civil servants that growing demand for school places, combined with a drive for schools to make efficiency savings, would only build pressure in the system.
"Instead they seem to have watched on, scratching their heads, as more and more teachers quit the profession.
"Government must get a grip on teacher retention and we expect it to set out a targeted, measurable plan to support struggling schools as a matter of urgency.
"There is a real danger that, without meaningful intervention from Government, these challenges will become an intractable threat to children's education."
Labour's shadow education secretary Angela Rayner said: "This Conservative Government is presiding over a crisis in teacher recruitment and retention; missing their own targets five years in a row, with demoralised teachers leaving the profession in record numbers.
"Their cap on public sector pay has left the average teacher over £5,000 worse off and makes it impossible for many schools to retain the staff that they need."
A Department for Education spokesman said: "There are now a record number of teachers in our schools - 15,500 more than in 2010 - and last year, despite a competitive labour market with historic low unemployment rates and a growing economy, 32,000 trainee teachers were recruited.
"Retention rates have been broadly stable for the past 20 years and the teaching profession continues to be an attractive career.
"We want to continue to help schools recruit and retain the best teachers.
"We are consulting on proposals to improve and increase development opportunities for teachers across the country and working with teachers, unions and Ofsted to tackle unnecessary workload with specific support for teachers at the start of their careers.
"Alongside this, we continue to offer financial incentives to attract the brightest and best into our classrooms."