Figures showed last week that the number of seven-year-olds who were competent in reading, writing and maths had fallen, and all the Government’s key targets for 11-year-olds were missed. But the primary school results were published at exactly the same time — 9.30am on Thursday, August 24 — as GCSE results, which dominate news bulletins every year. The timing was a break from tradition. In recent years primary school figures have been released on the Tuesday, two days before GCSEs.

The change led to allegations that ministers were trying to bury the damaging story of falling standards in primary schools and missed targets.

The Statistics Commission has now called for a formal explanation from the Department for Education and Skills. A formal investigation could follow. Richard Alldritt, chief executive of the Statistics Commission, said: “A concern was expressed to us that the timing of the release changed for reasons of political advantage or news management.

“Having had a verbal assurance from the DfES that that is not true, we have asked them for something in writing. We will consider whether to pursue the matter.”

It was understood that the commission had received a letter from the head of statistics at the DfES but had not yet been able to consider it.

The code of practice on government statistics states that figures should be released as soon as they become available. Holding back primary school results — even for two days — in an attempt to gain political advantage would risk breaking the spirit of the code, if not the letter, according to sources at the commission.

If the commission found against the Government it would revive the damaging charges of “spin” laid against ministers since 1997 and which they have been desperately trying to counter.

Perhaps the most damaging example was when Jo Moore, who was a special adviser at the Transport Department, sent an e-mail to colleagues in which she suggested that the terrorist attacks on September 11, 2001, made it a good day to bury bad news.

David Willetts, the Shadow Education Secretary, told The Times Educational Supplement that people might suspect that ministers were trying to “bury” the bad news of the primary school results. “If so, it would not be the first time the Government has sought to bury bad news in this way,” he said.

But a spokesman for the Department for Education and Skills rejected the suggestion. “The Statistics Commission has not launched an inquiry and we do not believe there is any reason for them to do so,” he said. “The publication of the data was carried out in accordance with the rules governing the publication of national statistics.”

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