Some compulsory test papers taken by primary school children in Norfolk have been returned to them unmarked.
Keith Wright, head of Barnham Broom Primary School near Norwich, said some pupils did not get results from the Standard Assessment Tasks (Sats).
He wants markers at Educational Testing Service (ETS) made accountable and said some pupils were very disappointed.
ETS took over marking this year. It said it dealt with 8.5m papers in six weeks and problems were inevitable.
The pupils, taking key Stage 2 tests in English, maths and science, expected their results before going to secondary schools next term.
Mr Wright said: "The children worked so hard for these tests. We get condemned if our levels are not up to scratch and I don't see why these people or whoever is responsible should not be made accountable.
"It's just not acceptable."
Immediate response
Tom Ewing, a spokesman for ETS, said that a small number of scripts had been returned to schools unmarked.
"It is inevitable some would get mixed up with marked papers as we dealt with 8.5m scripts.
"But as soon as we were informed by the schools we arranged for them to be collected and sent again for marking.
"We took immediate steps to rectify the situation and the scripts will be marked as soon as possible."
According to its website ETS is a non-profit organisation "with the mission to advance quality and equity in education by providing fair and valid assessments, research and related services for all people worldwide".
Founded in 1947, ETS designs, develops, delivers and scores more than 50 million tests annually in more than 180 countries, at more than 9,000 locations worldwide.
ETS is based at Watford in the UK and its European headquarters is in Amsterdam, Holland.
^ Back to top | BBC Sport Home | BBC Homepage | Contact us | Help | ©
~RS~q~RS~~RS~z~RS~19~RS~)