School and college leaders are demanding Ofqual come clean over why students might have grades “withheld” this summer.

Ofqual’s chair and chief regulator last week warned results could be withheld should an exam board and school or college not agree on the teacher-assessed grade awarded.

But Geoff Barton, general secretary of the Association of School and College Leaders (ASCL), said the guidance for schools and colleges only contained the “vaguest of the vague” references to results being withheld.

There was “no explanation” of the process.

“We have asked these questions, but have not been able to elicit any further information.”

He called for Ofqual and the Joint Council of Qualifications (JCQ) – the board representing exam boards – to have “a clear process in place and an answer about how such a dispute would ultimately be resolved if grades were to be withheld.

“Obviously, everybody hopes that no such impasse will happen, but it is a good idea to have it mapped out at this stage so that it is clear and is not left hanging in the air.”

At the third stage of quality assurance this year, exam boards will conduct random and targeted checks on the evidence used to determine teacher-assessed grades.

JCQ guidance published in March said a board would decide whether to accept the grades submitted or undertake further review, which “may lead to the withholding of results”.

Ian Bauckham, Ofqual’s interim chair, last week said boards “reserve the right to withhold or delay the publication of results if it  is not possible to agree an acceptable way forward in such cases”.

Ofqual said this week it expected exam boards to resolve concerns through “professional dialogue”. Results would only be withheld in “rare cases”.

“As in any year where an exam board has remaining concerns about any result, this is an important safeguard to protect the integrity of qualifications.”

JCQ said in any exam series there were “isolated circumstances” where a student’s grade may not be available on results day.

Where issues were “unresolved”, exam boards “reserve the right to temporarily withhold results pending any further investigation required”.

Boards could use the no result code – (X) – where a result was not issued because the candidate was not due to receive one.

Code X could also be used because of malpractice investigations.

Pending – (Q) – indicates that no result has been issued as the grade was not yet available.

In 2018-19, about 0.3 per cent of GCSE entries (14,094) were “no result” – but it is not broken down by X or Q grades in government data