Plans to overhaul A-level geography have been delayed by a year after academics raised serious concerns that the qualification is not yet "fit for purpose".
A new A level in the subject was due to be introduced to schools and colleges in September next year as part of a major government overhaul of the exams system.
But a group of academics, led by Professor Mark Smith, vice-chancellor of Lancaster University, has warned of "fundamental issues" with the content of the qualification, and called on ministers to delay reform of the A level so that these can be addressed.
It means that the qualification will now not be brought in until September 2016 - at the same time as new A levels in maths and languages are due to be introduced.
In a letter to education secretary Michael Gove, Professor Smith, who has been chairing a review of A-level content in key subjects, said that a consultation on the subject had raised "a number of fundamental issues about the proposed content".
As a result, "significant work is required before it can be considered fit for purpose", the letter said.
Professor Smith concluded: "Due to the fundamental nature of the further work required and because awarding organisations have already confirmed they will not be in a position to make the changes in time for first teaching in September 2015, I strongly recommend delaying the reform of geography A-level until September 2016."
In his response, Mr Gove said he accepted the recommendation to allow changes to be considered, "in particular to ensure that the level of challenge is high enough".
A Department for Education spokesman said: "Professor Smith and the A-level review panels are currently considering evidence on subject content to ensure all new A levels properly prepare young people for rigorous degree subjects and match the world's best.
"In the case of geography, they have identified that significant work will be needed to ensure the new A level is as high-quality and challenging as it needs to be."
The newly established A-level Content Advisory Board (ALCAB), which is being set up by leading universities' body the Russell Group, has been asked to advise on the content of A-level geography. It is also looking at maths and languages.
The Royal Geographical Society (RGS) welcomed the decision, saying in a statement that it had been concerned that previous proposals for the content of the qualification were "highly repetitive of the new draft GCSE content".
The delay comes just months after England's exams regulator Ofqual put the brakes on reforms to a number of GCSEs and A levels.
In September it said that revamped A levels in maths and further maths should be put back a year to 2016 after a report found that "fundamental work" was needed to improve A levels in these subjects.
Mr Gove said at the time that he agreed with delaying changes to maths and further maths, given their "fundamental importance".
It had always been intended that new languages A levels would be introduced in 2016.
It means that A levels in English language, English literature, the sciences, history, psychology, art and design, sociology, business studies, economics and computing are now expected to be ready for teaching next year.
Ofqual has also called for delays to new GCSEs, saying that it could not be confident that high-quality qualifications in all subjects could be ready for 2015.
The recommendation was accepted by ministers and new GCSEs in English language, English literature and maths will be introduced next year, with other subjects following later.