There is a high risk of another national tests disaster this summer, England's former assessment chief warned this week as he launched a devastating attack on ministers for their part in last year's shambles.
Ken Boston, former chief executive of the Qualifications and Curriculum Authority, told MPs that the root cause of the problems last year was an "archaic" marking system which the Government had chosen not to reform.
Ministers' evidence to the Sutherland inquiry into the 2008 marking scandal - in which results were delayed for 1.2 million pupils - was "sexed up" and "fiction", and the conditions remained for a repeat this year, he said.
"Every year this has been a high-wire act," Dr Boston told the Commons schools select committee. "It is to do with the extraordinarily large scope of the job packed into eight weeks."
The QCA had recommended more reliable computerised on-screen marking to ministers, but they had rejected it as "too risky".
The system had failed in 2004, been hours from failing in 2005 and collapsed in 2008," said Dr Boston. Today, it remained the "cottage industry" it was in 2002 and the axeing of key stage 3 Sats would not have halved the risk, he said.
He added: "The whole archaic nature of the thing is incredible and we are persisting with it for 2009. The margins for error, the risks in this, are so high. I can't see these tests ever having a risk rating of less than amber."
The Sutherland report recommended on-screen marking, and the Government is considering whether it should be introduced from 2010. A spokesman for the Department for Children, Schools and Families said it had every confidence in the delivery of this year's tests.
Dr Boston, whose resignation over last summer's failure was accepted earlier this month, warned that the two bodies replacing the QCA would struggle for independence.
He had supported the setting up of Ofqual, the new qualifications regulator, but feared it had made a "mistake" by letting government observers attend its meetings.
Ministers had compromised its autonomy by asking it to set terms of reference for the Sutherland inquiry that covered the QCA and the tests contractor ETS, but not government. The intervention had "put a protective fence around DCSF ministers", Dr Boston said.
He added: "Ofqual was made to stumble at its first hurdle, and that is not an auspicious sign for an independent regulator.
"The greatest risk for Ofqual at the moment is being cynically outmanoeuvred by the Government."
He said the new Qualifications and Curriculum Development Agency would be so under the control of government that it might as well be incorporated into the DCSF.
Dr Boston had expressed his opposition to the new development agency at a tense meeting with ministers in March 2008, when it was clear they saw him as a "troublesome priest".
Relations did not recover, with the later test problems acting as a further "catalyst" for his departure. DCSF officials had asked him to resign before ministers had even given evidence to the Sutherland inquiry.
Dr Boston said ministers' claims that they had "pressed" him for answers over the 2008 tests were false, and he criticised schools minister Jim Knight for telling the Sutherland inquiry that the two had spoken at a meeting which had not taken place, and for not correcting the error for weeks.
"There comes a time when a minister has to take account of everything and go," Dr Boston told MPs. But he later denied he was calling for ministerial resignations.