Pavich Thongroj said the answer sheets were not lost but had just been mixed with other files. He said the scores would be available online before May 9, which is the last day for university admission. Yesterday was the last day that students were allowed to check their scores and answer sheets and file complaints. Although Ohec promised that scores would be available on Friday, thousands of results were still unavailable on the Web late Friday night.

Khunying Sumontha Phromboon, chair of the National Institute of Educational Testing Services (NIETS), admitted that her office could send revised scores to only 10 per cent of the 2,000 students who had complained to Ohec.

Students were still complaining yesterday. At Chulalongkorn University, 245 complaints were made, mostly demanding that Thai-language papers be reviewed.

Eighteen students wanted their English answer papers to be re-marked, because they were still being given a score of zero, despite weeks of complaints. Sumontha said all complaints would be processed and the scores in need of revision would be updated online on a daily basis. Throughout the weeklong period during which students could file grievances with Ohec, Pavich said his office received 8,904 complaints, 6,467 of which had been processed.