One more push and national tests could be gone from English schools for ever. That is the hope of teachers’ and heads’ unions the NUT and NAHT, who are holding a conference on the future of assessment on Wednesday.

They want to build on the momentum of the decision to scrap Sats for 14- year-olds and persuade the Government to do the same for key stage 2 tests.

At first glance, that seems optimistic. When Ed Balls, the Schools Secretary, announced the end of compulsory KS3 testing in October, he said: “Key stage 2 tests are here to stay. They are essential to giving parents, teachers and the public the information they need about the progress of every primary-age child and every primary school.”

However, chinks of light are starting to emerge for the anti-testing lobby. Mr Balls used his announcement to commission a panel of five experts to examine outstanding issues on pupil assessment. One of them, the newly knighted Sir Tim Brighouse, plans to make some interesting comments at Wednesday’s conference.

The former commissioner for London schools told The TES he would look at the differences between education systems that had high levels of professional trust but low accountability and those, like England’s, that had high accountability but lower levels of trust. “I am going to come to the conclusion that we need a system where teachers are more trusted in their analysis of pupil progress,” he said.

That will be music to the ears of campaigners who want to see internal teacher assessment of pupils replace external national tests.

Sir Tim would not be drawn on whether the group of experts had, or would be, discussing such issues in its deliberations. Strictly speaking, they are outside its remit.

As far as KS2 is concerned, they have been asked to look only at evidence from the Government’s pilots of single-level progress tests and at “what advice should be provided to schools to ensure that preparation for national curriculum tests at key stage 2 is proportionate, educationally appropriate, and that the delivery of a broad and balanced curriculum is not inhibited”.

But the NUT and NAHT argue in a joint statement that whatever advice the experts give about cutting preparation time for testing, it will be largely irrelevant while the high-stakes nature of the system remains.

“The fact that percentages of test results are used as national floor targets, and that early inspection and aggressive local authority intervention can be triggered by schools failing to reach test result targets, will mean that teachers under pressure to maximise the number of level 4s in English and maths will largely ignore such advice,” the statement says. In other words, the fact that tests are used to hold schools to account conflicts with their supposed purpose of helping pupils to make progress.

It is a problem Sir Tim obviously understands. He plans to outline the various purposes of the tests on Wednesday. He says they also include the need to make national and international comparisons, to help teachers improve and give parents information. “What I think we need is an analysis of what we are doing under any one of those purposes, and an assessment of what could possibly be changed to improve any one of them and to avoid any one of them distorting the other,” he said.

“In countries with high-stakes accountability systems where those high stakes are narrowly focused, the curriculum is narrowed and the pupil’s experience is narrowed. That is what some people think is happening at key stage 2.”

With Sir Tim and the other members of the panel due to meet next week and report by the end of the month, the timing of his comments is interesting.

It is also worth noting that he is not the only one of the experts to have made statements suggesting the Government should give further ground on testing.

When Sir Jim Rose published his interim report on the primary curriculum in December, he admitted that national tests - which he was ruled out of reviewing because they are not part of the curriculum - had been the “elephant in the room”. “I think it’s such a big question,” he said. “If concerns are such, it should be reviewed separately.”

Another encouraging point for anti-testers is that a common interlocking analysis of what is wrong with the tests and what should be used as a solution seems to be emerging. The argument in essence is that it is not the tests themselves, but the uses that the results are put to that create the problem. As Sir Tim suggests, there is risk that their disparate and potentially conflicting functions can create distortions.

Christine Merrell, primary director of Durham University’s Centre for Evaluation and Monitoring, will suggest a solution to that problem on Wednesday, recommending the creation of separate systems for monitoring standards and pupils’ progress.

She says the reliability of the tests is adequate for schools to use for the internal monitoring of pupil progress. The problems emerge when pupils’ individual test scores are converted into cruder national curriculum levels.

Pupils can have off days and a single mark can lead to them having a completely different level. Dr Merrell will point to research by Professor Dylan Wiliam, deputy director of the Institute of Education in London, suggesting that around a quarter of pupils are classified with the wrong national curriculum level during this process.

The problem is magnified when schools with as few as 11 pupils taking the tests are judged on the national curriculum scores. Just one misclassified pupil could account for 10 per cent of the school’s score.

“When you are using these result for league tables, it can distort people’s impressions of schools,” Dr Merrell said.

“With the current testing arrangements, there are problems at the pupil level, the school level and that national level.”

The NUT and NAHT want to see internal teacher assessment used to track individual pupil progress. Sample test data measuring progress in different parts of the curriculum in different schools could be collected to measure national standards, but school league tables would disappear.

The Government insists that a testing system should “give parents the information they need to compare different schools”.

But opposition is only likely to grow. A small-scale NUT survey this week found that three-quarters of teachers wanted to see the end of KS2 tests.

Even more significant is the NAHT survey of parents. If 75 per cent of them do not think league tables are a real measure of schools, then is there any point in retaining the tests used to compile them?

A ministerial U-turn on KS2 tests still seems unlikely. But then, so did October’s decision on KS3.

What primary and secondary staff told the NUT about national tests

- It is shameful that primary-age children will still be subjected to these abhorrent tests. English children are the “unhappiest” in Europe. It’s time we give them their childhood back.

- Data interpretation questions in the Sats papers were valuable resources for teachers and pupils to think about scientific problems - they were enhancing critical thinking processes.

- The Sats testing regime has crippled real education in our schools. If the Sats regime is sufficiently discredited for the Government to abandon it at KS3, how can they justify retaining it at KS2?

- The examination system and marking of exams are riddled with inconsistencies. Mark schemes are dressed up to appear objective, but in many subjects they are incapable of doing the job they are meant to do.

- Give schools a chance. They know their pupils.

- As a Year 2 teacher, I spend a lot of my time reassuring parents about the Sats. They are very concerned that their children have to sit exams at such an early age, and when they understand that their children are assessed throughout the year, they cannot understand why the Sats exist.

- Single-level tests could be out of the frying pan.

- Why is England the only country in the UK still testing 11-year- olds?

- I am disappointed with my school’s lack of imagination when it comes to KS3. It will still be using the national curriculum tests in Year 9 and nothing will change. Is this lack of drive and inability to take risks a national epidemic in schools?

- Please make sure the workload of assessing pupils does not fall back on teachers, instead of paid markers. There must be no additional workload for teachers involved in this decision (to end compulsory KS3 tests).

- There is absolutely no need to test children before they reach secondary school. Focus on what children can do, give them a thirst for learning, not a fear of failing.