A primary school has been criticised for waiting until the last day of term to formally tell parents year 6 pupils will not get their overall result as their SATS papers have been lost.

A copy of the letter, dated July 2 from the Standards and Testing Agency (STA) to Selwyn Primary School, outlining the 81 lost papers, was given to pupils today.

There are currently 83 pupils enrolled in year 6 at the Cavendish Road school in Highams Park.

According to the letter, the STA said it was unable to return overall results for key stage 2 mathematics and key stage 2 grammar, punctuation and spelling as they were "unable to locate" 81 test scripts for levels 3-5 mental mathematics and level 3-5 spelling.

Results were published on July 7, with the letter stating parents should be informed about the lost papers.

A letter was sent out to parents on July 10 informing them of a meeting on July 15 where pupils' results will be shared, but it did not mention the lost papers, only "we have some key information to share with you in addition to results."

It is understood the missing marks have been made up using the average of three previous practice SATS tests.

Executive headteacher at Selwyn Primary School, Maureen Okoye, told the Guardian: "We are extremely disappointed that our year 6 pupils will not receive their overall SATs examination score as some of their papers have been lost by the Standards and Testing Agency.

"Pupils, parents, teachers and governors all work hard to make sure that the examination process is a success and the results from the papers that we have marked internally show that as a school we were on track to be well above the national average.

"The Standards and Testing Agency are currently investigating the matter.

"We have notified our year 6 parents and pupils who are understandably upset by the situation and the loss of their hard work."

Parent Karen Murray, said her 11-year-old daughter received her results on Friday.

She said: "I came to the school office with several other parents on Friday to ask for an explanation on what was going on.

"Ms Bogle saw us separately and showed us the STA letter but said we couldn't have a copy because of 'legal reasons'.

"Parents have been told at different times, there are definitely parents that still do not know now.

"The lack of communication has been really poor, parents haven't even been told how the marks would be made up.

"When they got the letter on July 2, why weren't procedures in place?

"Some kids got theirs, some didn't and there were some kids crying because they didn't if they were getting their results or not.

"The whole thing has been badly managed."

A spokesman for the STA, said: "We wrote to Selwyn Primary School on July 2 to notify them that levels for the key stage 2 maths tests and grammar, punctuation and spelling tests would not be returned for 81 pupils.

"Our investigations suggest it is likely they went missing during collection from the school."