TEACHERS have been refusing to grade this year’s national curriculum English tests for 14-year-olds because of difficulties applying the marking scheme, The TES understands.

Markers contracted to Britain’s biggest exam board have been returning tests ungraded because of problems trying to find an accurate level for pupils’ work.

The AQA board is now facing a struggle to ensure that papers are marked by the end of term. It has asked senior markers who have retired from the classroom to work full-time for the next few weeks processing papers.

The problem is the latest in a series to hit the revamped English tests, which AQA marks for the Qualifications and Curriculum Authority and which have been controversial since details of the changes emerged last year.

For the first time this year, markers are asked to assess pupils’ work against criteria which are not linked to a specific national curriculum level.

For example, in one of the two writing tests, pupils are given a mark on sentence structure and punctuation, text structure and composition. The marks are then totted up to arrive at a level.

Sats experts have complained that the mark scheme leaves open the possibility that students could score no marks in particular sections despite displaying fairly sophisticated uses of language.

Teachers have been unsure about what marks to allocate to the writing elements of the tests in particular. One senior subject association source said that some were taking so long over papers, they were only earning pound;4 an hour. Markers are paid pound;3.50 per script.

The source added: “People are finding the mark scheme impossible to apply.

Some of them say that the reading is difficult. Many of them say that the writing mark scheme is impossible to apply. A lot are sending their papers back and saying that they cannot do it.”

One marker, who asked not to be named, said: “The papers are taking a long time to mark.”

The AQA and the QCA have found it particularly difficult to recruit markers for the key stage 3 English tests, taken by 600,000 pupils in 5,500 schools this year.

Only a month ago, they were forced to advertise for newly-qualified teachers to come forward to mark this year’s scripts.

Recruitment may also have been affected by the fact that the tests, which the QCA says provide a better gauge of pupils’ abilities, have been attacked by some teachers as “atomistic“or fragmented in favouring easily-measurable aspects of English.

The London Association for the Teaching of English has been running a campaign urging teachers to boycott marking them. The National Union of Teachers is to ballot its members on refusing to administer next year’s tests.

The QCA said that the number of contracted markers dropping out was the same as in recent years but it would not give figures.

John Green, lead chief marker for key stage 3 English tests, said that when the marking schemes were published in the autumn, teachers had found them “intimidating”.

Teachers had been expected to take longer to mark the tests: four to five an hour compared to six or seven under the old system.

But he said that extra markers had been taken on to reflect this, that all had received training and that the marking was progressing relatively smoothly.

A QCA spokeswoman added that every year experienced markers were asked to take on extra scripts.