As with many taxpayer-funded fiascos, the allocation of blame for this summer’s Sats debacle is not an easy exercise.

With agencies, civil servants and private sector companies wrapped up in a host of legal and quasi-legal relationships, any bid to unravel exactly what happened is bound to be fraught with difficulty.

This point was illustrated beautifully last week when ETS Europe, the company charged with marking this year’s exams, gave evidence before the House of Commons select committee for children, schools and families.

“Despite what you might have heard,” the company’s representatives seemed to be saying, “it wasn’t really our fault.

“It was the others. It was down to them.”

At first it seemed like a breathtaking claim - the company that was being paid pound;156 million over five years to oversee the markers, the marking and the distribution of papers was claiming that the bulk of the blame should lie with the government agency that appointed them, the National Assessment Agency, the examinations arm of the Qualifications and Curriculum Authority.

But, as Warwick Mansell’s analysis shows, one cannot ignore the fact that the QCA did oversee a nine-month procurement process that culminated in ETS winning the contract.

Surely the QCA should have spotted any institutional weaknesses in the company.

Only one thing is clear: this blame game is far from over.

Watch this space as the government-commissioned Sutherland inquiry prepares to report back later this autumn. There could be fireworks.