In the document, based on the evidence submitted, Lord Bew said it was increasingly clear there would be no single set of solutions which would command universal support, but that reform was needed.

He added that the review is: “committed to bringing about meaningful, fair and lasting improvements”.

There have been 4,000 responses to the review and 50 people have spoken in formal evidence sessions. It found 50 per cent of respondents wanted league tables removed and 47 per cent felt the current system encouraged schools to “teach to the test” and narrowed the curriculum.

It also found strong evidence that external school-level accountability is important in driving up achievement and improving pupils’ progress.

The review group has a remit to look at how assessment can improve standards and ensure accountability while avoiding teaching to the test. It is also looking at how to make the system as simple and cost-effective as possible. Its recommendations on how to do this will be included in the final report in June.

Russell Hobby, general secretary of heads’ union the NAHT, which staged a boycott of the tests last year that 25 per cent of schools supported, said: “I was pleased with the progress report. I thought that it was balanced. Anyone reading it wouldn’t hesitate to change what we have.

“But the ideas the review panel has to improve it could be very different from ours. Our strategy remains as it was. We will wait for the report in June and our branches will then make choices about whether it has gone far enough.”

Andrew Carter, head of South Farnham Junior School, Surrey, ran the tests last year. He said: “I believe they have been a lever for school improvement. The key thing to do is just not publish the results nationally because everybody is worried about their place in the league tables.

“There are people who don’t like tests because they feel it is an incorrect way to judge a child’s learning, but then you have to come up with a way that is at least as good and preferably better.”

NUT general secretary Christine Blower said: “The report provides confirmation that the majority of those working in primary education believe change in KS2 assessment and accountability is long overdue.

“It also confirms that teachers and headteachers have no problem with schools being accountable for their performance. What they object to is the unfair and crude way in which this is done.”

Original headline: Sats review chair calls for reform of key stage 2 tests