Education secretary Michael Gove has confirmed he is not pressing ahead with plans to scrap GCSEs, telling the Commons on Thursday his proposals were "a bridge too far".
Gove has been forced to abandon his flagship plan to scrap GCSEs and replace them with a new English Baccalaureate.
The move was said to follow pressure from within the coalition from the Liberal Democrats as well as criticism from MPs across the political spectrum.
Christine Blower, general secretary of the National Union of Teachers, told BBC Radio 5 live that she's "absolutely delighted".
"Introducing the Ebacc was entirely the wrong thing to do especially in the timescale that Mr Gove had in mind. We think this is a very good move and we are very pleased."
Last week the cross-party Commons Education Committee said the Government had "not proved its case" that GCSEs should be abolished in key academic subjects.
Labour said that it was a "humiliating climbdown" for one of the most high-profile members of the Cabinet.
Gove told MPs instead of new qualifications, GCSEs will be reformed, with exams taken at the end of the course, rather than in modules, extended questions and less internal assessment.
He also confirmed that he will not be pressing ahead with plans to hand each of the core EBC subjects to a single exam board - a move he had previously argued was essential to prevent boards "dumbing down" standards to attract more schools.
"Last September we outlined plans for changes to GCSE qualifications designed to address the grade inflation, dumbing down and loss of rigour in those examinations," Gove told the Commons on Thursday.
"We have consulted on those proposals and there is now a consensus that the system needs to change. But one of the proposals I put forward was a bridge too far.
"My idea that we end the competition between exam boards to offer GCSEs in core academic qualifications and have just one - wholly new - exam in each subject was just one reform too many at this time.
"The exam regulator Ofqual - which has done such a great job in recent months upholding standards - was clear that there were significant risks in trying to both strengthen qualifications and end competition in a large part of the exams market.
"So, I have decided not to make the best the enemy of the good.
"And I will not proceed with plans to have a single exam board offering a new exam in each academic subject - instead we will concentrate on reforming existing GCSEs along the lines we put forward in September."
He had originally wanted to introduce the new EBacc certificate in England in the five core academic areas of English, maths, science, languages and humanities - history or geography.
Each of the core subjects would have been handed to a single examination board - a move he argued was essential to prevent boards "dumbing down" standards to attract more schools.
Shadow education secretary Stephen Twigg said Gove should have listened to warnings that the scheme would not work.
"This is a humiliating climbdown from Michael Gove," he said.
"It shows why he should have listened to business leaders, headteachers and experts in the first place and not come up with a plan on the back of an envelope.
"Pupils and parents need certainty now. Michael Gove must now make clear whether he will abandon his narrow, out of date plans altogether or merely try to delay them.
"He needs to go back to the drawing board and develop a curriculum and exam system that meets our future challenges as a country.
"Labour wants to work with the Government to forge a long term consensus on exam and curriculum reform. We would welcome cross party talks."
A Department for Education source said: "We do not comment on leaks. Mr Gove will make a statement to the House."
Toni Pearce, the National Union of Students' vice president for further education added: "Michael Gove’s climb down is a victory for the alliance of students, parents, and teachers which steadfastly opposed his past their sell-by-date proposals.
"These plans would have created a narrow and unbalanced curriculum at just the time we need a flexible and open approach.
“The Education Secretary’s attempt to relegate high quality creative and vocational subjects to a non-essential second tier smacked of his 1950s prejudices rather than the long-term interests of today’s young people."
Voice, the union for education professionals, also welcomed Thursday's news.
General secretary Deborah Lawson said: “This is astonishing but welcome news. On Tuesday evening, Michael Gove was praising and promoting the EBacc in a speech to the Social Market Foundations. On Thursday morning, we learn that he will scrap the idea. This raises serious questions about his judgement and his future as Education Secretary.
“In that address, Mr Gove made headlines for dismissing aspects of the curriculum as ‘vapid happy talk’. Now it seems that the speech itself will remembered for being just that."