Education Secretary Michael Gove will appear before MPs on Wednesday as the row over GCSE English grades descended into farce.
A Welsh exam board has called on regulators in the principality and England to agree on a "common view" on how to resolve the crisis.
The WJEC exam board - previously the Welsh Joint Education Committee - made the plea after Welsh education minister Leighton Andrews ordered it to re-award its English language GCSE following a Welsh Government review.
But with the regulator in England, Ofqual, standing firm on the issue, WJEC, which sets GCSEs in both nations, is in the unusual position of having to regrade exam papers sat by pupils on one side of the border but not the other.
Gove has refused to intervene despite warning that GCSEs are "unfit for purpose".
Ministers should not "meddle" in decisions made by Ofqual, which is an independent regulator, he said.